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* zram: drop not used table `count' memberSergey Senozhatsky2016-06-051-1/+0
| | | | | | | | | | | struct table `count' member is not used. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: report failed read and write statsSergey Senozhatsky2016-06-051-0/+4
| | | | | | | | | | | | | zram accounted but did not report numbers of failed read and write queries. make these stats available as failed_reads and failed_writes attrs. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: remove zram stats code duplicationSergey Senozhatsky2016-06-051-59/+23
| | | | | | | | | | | | Introduce ZRAM_ATTR_RO macro that generates device_attribute and default ATTR show() function for existing atomic64_t zram stats. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: use atomic64_t for all zram statsSergey Senozhatsky2016-06-052-12/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | This is a preparation patch for stats code duplication removal. 1) use atomic64_t for `pages_zero' and `pages_stored' zram stats. 2) `compr_size' and `pages_zero' struct zram_stats members did not follow the existing device attr naming scheme: zram_stats.ATTR has ATTR_show() function. rename them: -- compr_size -> compr_data_size -- pages_zero -> zero_pages Minchan Kim's note: If we really have trouble with atomic stat operation, we could change it with percpu_counter so that it could solve atomic overhead and unnecessary memory space by introducing unsigned long instead of 64bit atomic_t. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: remove good and bad compress statsSergey Senozhatsky2016-06-052-13/+0
| | | | | | | | | | | | | | | | | | Remove `good' and `bad' compressed sub-requests stats. RW request may cause a number of RW sub-requests. zram used to account `good' compressed sub-queries (with compressed size less than 50% of original size), `bad' compressed sub-queries (with compressed size greater that 75% of original size), leaving sub-requests with compression size between 50% and 75% of original size not accounted and not reported. zram already accounts each sub-request's compression size so we can calculate real device compression ratio. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: do not pass rw argument to __zram_make_request()Sergey Senozhatsky2016-06-051-19/+13
| | | | | | | | | | | | | | | | | | Do not pass rw argument down the __zram_make_request() -> zram_bvec_rw() chain, decode it in zram_bvec_rw() instead. Besides, this is the place where we distinguish READ and WRITE bio data directions, so account zram RW stats here, instead of __zram_make_request(). This also allows to account a real number of zram READ/WRITE operations, not just requests (single RW request may cause a number of zram RW ops with separate locking, compression/decompression, etc). Change-Id: Ibc8aa078d076ea84fb952eac6877ac48493e7288 Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: drop `init_done' struct zram memberSergey Senozhatsky2016-06-052-11/+11
| | | | | | | | | | | | | Introduce init_done() helper function which allows us to drop `init_done' struct zram member. init_done() uses the fact that ->init_done == 1 equals to ->meta != NULL. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: avoid null access when fail to alloc metaMinchan Kim2016-06-051-0/+2
| | | | | | | | | | | zram_meta_alloc could fail so caller should check it. Otherwise, your system will hang. Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: remove zram->lock in read path and change it with mutexMinchan Kim2016-06-052-12/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Finally, we separated zram->lock dependency from 32bit stat/ table handling so there is no reason to use rw_semaphore between read and write path so this patch removes the lock from read path totally and changes rw_semaphore with mutex. So, we could do old: read-read: OK read-write: NO write-write: NO Now: read-read: OK read-write: OK write-write: NO The below data proves mixed workload performs well 11 times and there is also enhance on write-write path because current rw-semaphore doesn't support SPIN_ON_OWNER. It's side effect but anyway good thing for us. Write-related tests perform better (from 61% to 1058%) but read path has good/bad(from -2.22% to 1.45%) but they are all marginal within stddev. CPU 12 iozone -t -T -l 12 -u 12 -r 16K -s 60M -I +Z -V 0 ==Initial write ==Initial write records: 10 records: 10 avg: 516189.16 avg: 839907.96 std: 22486.53 (4.36%) std: 47902.17 (5.70%) max: 546970.60 max: 909910.35 min: 481131.54 min: 751148.38 ==Rewrite ==Rewrite records: 10 records: 10 avg: 509527.98 avg: 1050156.37 std: 45799.94 (8.99%) std: 40695.44 (3.88%) max: 611574.27 max: 1111929.26 min: 443679.95 min: 980409.62 ==Read ==Read records: 10 records: 10 avg: 4408624.17 avg: 4472546.76 std: 281152.61 (6.38%) std: 163662.78 (3.66%) max: 4867888.66 max: 4727351.03 min: 4058347.69 min: 4126520.88 ==Re-read ==Re-read records: 10 records: 10 avg: 4462147.53 avg: 4363257.75 std: 283546.11 (6.35%) std: 247292.63 (5.67%) max: 4912894.44 max: 4677241.75 min: 4131386.50 min: 4035235.84 ==Reverse Read ==Reverse Read records: 10 records: 10 avg: 4565865.97 avg: 4485818.08 std: 313395.63 (6.86%) std: 248470.10 (5.54%) max: 5232749.16 max: 4789749.94 min: 4185809.62 min: 3963081.34 ==Stride read ==Stride read records: 10 records: 10 avg: 4515981.80 avg: 4418806.01 std: 211192.32 (4.68%) std: 212837.97 (4.82%) max: 4889287.28 max: 4686967.22 min: 4210362.00 min: 4083041.84 ==Random read ==Random read records: 10 records: 10 avg: 4410525.23 avg: 4387093.18 std: 236693.22 (5.37%) std: 235285.23 (5.36%) max: 4713698.47 max: 4669760.62 min: 4057163.62 min: 3952002.16 ==Mixed workload ==Mixed workload records: 10 records: 10 avg: 243234.25 avg: 2818677.27 std: 28505.07 (11.72%) std: 195569.70 (6.94%) max: 288905.23 max: 3126478.11 min: 212473.16 min: 2484150.69 ==Random write ==Random write records: 10 records: 10 avg: 555887.07 avg: 1053057.79 std: 70841.98 (12.74%) std: 35195.36 (3.34%) max: 683188.28 max: 1096125.73 min: 437299.57 min: 992481.93 ==Pwrite ==Pwrite records: 10 records: 10 avg: 501745.93 avg: 810363.09 std: 16373.54 (3.26%) std: 19245.01 (2.37%) max: 518724.52 max: 833359.70 min: 464208.73 min: 765501.87 ==Pread ==Pread records: 10 records: 10 avg: 4539894.60 avg: 4457680.58 std: 197094.66 (4.34%) std: 188965.60 (4.24%) max: 4877170.38 max: 4689905.53 min: 4226326.03 min: 4095739.72 Change-Id: I59cc9c518bdeddb5b82f1b43aa674291161626bf Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: remove workqueue for freeing removed pending slotMinchan Kim2016-06-052-58/+6
| | | | | | | | | | | | | | | | | Commit a0c516cbfc74 ("zram: don't grab mutex in zram_slot_free_noity") introduced free request pending code to avoid scheduling by mutex under spinlock and it was a mess which made code lenghty and increased overhead. Now, we don't need zram->lock any more to free slot so this patch reverts it and then, tb_lock should protect it. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: introduce zram->tb_lockMinchan Kim2016-06-052-6/+23
| | | | | | | | | | | | | | | | | | | | | Currently, the zram table is protected by zram->lock but it's rather coarse-grained lock and it makes hard for scalibility. Let's use own rwlock instead of depending on zram->lock. This patch adds new locking so obviously, it would make slow but this patch is just prepartion for removing coarse-grained rw_semaphore(ie, zram->lock) which is hurdle about zram scalability. Final patch in this patchset series will remove the lock from read-path and change rw_semaphore with mutex in write path. With bonus, we could drop pending slot free mess in next patch. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: use atomic operation for statMinchan Kim2016-06-052-20/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some of fields in zram->stats are protected by zram->lock which is rather coarse-grained so let's use atomic operation without explict locking. This patch is ready for removing dependency of zram->lock in read path which is very coarse-grained rw_semaphore. Of course, this patch adds new atomic operation so it might make slow but my 12CPU test couldn't spot any regression. All gain/lose is marginal within stddev. iozone -t -T -l 12 -u 12 -r 16K -s 60M -I +Z -V 0 ==Initial write ==Initial write records: 50 records: 50 avg: 412875.17 avg: 415638.23 std: 38543.12 (9.34%) std: 36601.11 (8.81%) max: 521262.03 max: 502976.72 min: 343263.13 min: 351389.12 ==Rewrite ==Rewrite records: 50 records: 50 avg: 416640.34 avg: 397914.33 std: 60798.92 (14.59%) std: 46150.42 (11.60%) max: 543057.07 max: 522669.17 min: 304071.67 min: 316588.77 ==Read ==Read records: 50 records: 50 avg: 4147338.63 avg: 4070736.51 std: 179333.25 (4.32%) std: 223499.89 (5.49%) max: 4459295.28 max: 4539514.44 min: 3753057.53 min: 3444686.31 ==Re-read ==Re-read records: 50 records: 50 avg: 4096706.71 avg: 4117218.57 std: 229735.04 (5.61%) std: 171676.25 (4.17%) max: 4430012.09 max: 4459263.94 min: 2987217.80 min: 3666904.28 ==Reverse Read ==Reverse Read records: 50 records: 50 avg: 4062763.83 avg: 4078508.32 std: 186208.46 (4.58%) std: 172684.34 (4.23%) max: 4401358.78 max: 4424757.22 min: 3381625.00 min: 3679359.94 ==Stride read ==Stride read records: 50 records: 50 avg: 4094933.49 avg: 4082170.22 std: 185710.52 (4.54%) std: 196346.68 (4.81%) max: 4478241.25 max: 4460060.97 min: 3732593.23 min: 3584125.78 ==Random read ==Random read records: 50 records: 50 avg: 4031070.04 avg: 4074847.49 std: 192065.51 (4.76%) std: 206911.33 (5.08%) max: 4356931.16 max: 4399442.56 min: 3481619.62 min: 3548372.44 ==Mixed workload ==Mixed workload records: 50 records: 50 avg: 149925.73 avg: 149675.54 std: 7701.26 (5.14%) std: 6902.09 (4.61%) max: 191301.56 max: 175162.05 min: 133566.28 min: 137762.87 ==Random write ==Random write records: 50 records: 50 avg: 404050.11 avg: 393021.47 std: 58887.57 (14.57%) std: 42813.70 (10.89%) max: 601798.09 max: 524533.43 min: 325176.99 min: 313255.34 ==Pwrite ==Pwrite records: 50 records: 50 avg: 411217.70 avg: 411237.96 std: 43114.99 (10.48%) std: 33136.29 (8.06%) max: 530766.79 max: 471899.76 min: 320786.84 min: 317906.94 ==Pread ==Pread records: 50 records: 50 avg: 4154908.65 avg: 4087121.92 std: 151272.08 (3.64%) std: 219505.04 (5.37%) max: 4459478.12 max: 4435857.38 min: 3730512.41 min: 3101101.67 Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: remove unnecessary freeMinchan Kim2016-06-051-8/+0
| | | | | | | | | | | | | | | Commit a0c516cbfc74 ("zram: don't grab mutex in zram_slot_free_noity") introduced pending zram slot free in zram's write path in case of missing slot free by memory allocation failure in zram_slot_free_notify but it is not necessary because we have already freed the slot right before overwriting. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: delay pending free request in read pathMinchan Kim2016-06-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Sergey reported we don't need to handle pending free request every I/O so that this patch removes it in read path while we remain it in write path. Let's consider below example. Swap subsystem ask to zram "A" block free by swap_slot_free_notify but zram had been pended it without real freeing. Swap subsystem allocates "A" block for new data but request pended for a long time just handled and zram blindly free new data on the "A" block. :( That's why we couldn't remove handle pending free request right before zram-write. Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: fix race between reset and flushing pending workMinchan Kim2016-06-051-2/+2
| | | | | | | | | | | | | | | | | | | Dan and Sergey reported that there is a racy between reset and flushing of pending work so that it could make oops by freeing zram->meta in reset while zram_slot_free can access zram->meta if new request is adding during the race window. This patch moves flush after taking init_lock so it prevents new request so that it closes the race. Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: add copyrightMinchan Kim2016-06-052-0/+2
| | | | | | | | | Add my copyright to the zram source code which I maintain. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zram: promote zram from stagingMinchan Kim2016-06-059-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Zram has lived in staging for a LONG LONG time and have been fixed/improved by many contributors so code is clean and stable now. Of course, there are lots of product using zram in real practice. The major TV companys have used zram as swap since two years ago and recently our production team released android smart phone with zram which is used as swap, too and recently Android Kitkat start to use zram for small memory smart phone. And there was a report Google released their ChromeOS with zram, too and cyanogenmod have been used zram long time ago. And I heard some disto have used zram block device for tmpfs. In addition, I saw many report from many other peoples. For example, Lubuntu start to use it. The benefit of zram is very clear. With my experience, one of the benefit was to remove jitter of video application with backgroud memory pressure. It would be effect of efficient memory usage by compression but more issue is whether swap is there or not in the system. Recent mobile platforms have used JAVA so there are many anonymous pages. But embedded system normally are reluctant to use eMMC or SDCard as swap because there is wear-leveling and latency issues so if we do not use swap, it means we can't reclaim anoymous pages and at last, we could encounter OOM kill. :( Although we have real storage as swap, it was a problem, too. Because it sometime ends up making system very unresponsible caused by slow swap storage performance. Quote from Luigi on Google "Since Chrome OS was mentioned: the main reason why we don't use swap to a disk (rotating or SSD) is because it doesn't degrade gracefully and leads to a bad interactive experience. Generally we prefer to manage RAM at a higher level, by transparently killing and restarting processes. But we noticed that zram is fast enough to be competitive with the latter, and it lets us make more efficient use of the available RAM. " and he announced. http://www.spinics.net/lists/linux-mm/msg57717.html Other uses case is to use zram for block device. Zram is block device so anyone can format the block device and mount on it so some guys on the internet start zram as /var/tmp. http://forums.gentoo.org/viewtopic-t-838198-start-0.html Let's promote zram and enhance/maintain it instead of removing. Change-Id: Ie8f4e47eb9b74f4269da921eb6c709964fb6753e Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Nitin Gupta <ngupta@vflare.org> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Bob Liu <bob.liu@oracle.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Conflicts: drivers/block/Kconfig drivers/staging/Kconfig drivers/staging/Makefile
* zsmalloc: add copyrightMinchan Kim2016-06-052-0/+2
| | | | | | | | | Add my copyright to the zsmalloc source code which I maintain. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* zsmalloc: move it under mmMinchan Kim2016-06-057-30/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch moves zsmalloc under mm directory. Before that, description will explain why we have needed custom allocator. Zsmalloc is a new slab-based memory allocator for storing compressed pages. It is designed for low fragmentation and high allocation success rate on large object, but <= PAGE_SIZE allocations. zsmalloc differs from the kernel slab allocator in two primary ways to achieve these design goals. zsmalloc never requires high order page allocations to back slabs, or "size classes" in zsmalloc terms. Instead it allows multiple single-order pages to be stitched together into a "zspage" which backs the slab. This allows for higher allocation success rate under memory pressure. Also, zsmalloc allows objects to span page boundaries within the zspage. This allows for lower fragmentation than could be had with the kernel slab allocator for objects between PAGE_SIZE/2 and PAGE_SIZE. With the kernel slab allocator, if a page compresses to 60% of it original size, the memory savings gained through compression is lost in fragmentation because another object of the same size can't be stored in the leftover space. This ability to span pages results in zsmalloc allocations not being directly addressable by the user. The user is given an non-dereferencable handle in response to an allocation request. That handle must be mapped, using zs_map_object(), which returns a pointer to the mapped region that can be used. The mapping is necessary since the object data may reside in two different noncontigious pages. The zsmalloc fulfills the allocation needs for zram perfectly [sjenning@linux.vnet.ibm.com: borrow Seth's quote] Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Nitin Gupta <ngupta@vflare.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Pekka Enberg <penberg@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Change-Id: Ib026c17143131089494dc394c4a35e230220ec83 Conflicts: drivers/staging/Kconfig drivers/staging/Makefile
* Staging: zram: Fix memory leak by refcount mismatchRashika Kheria2016-06-051-5/+14
| | | | | | | | | | | | | | | As suggested by Minchan Kim and Jerome Marchand "The code in reset_store get the block device (bdget_disk()) but it does not put it (bdput()) when it's done using it. The usage count is therefore incremented but never decremented." This patch also puts bdput() for all error cases. Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Staging: zram: Fix access of NULL pointerRashika Kheria2016-06-051-2/+4
| | | | | | | | | | | | | | | | | | This patch fixes the bug in reset_store caused by accessing NULL pointer. The bdev gets its value from bdget_disk() which could fail when memory pressure is severe and hence can return NULL because allocation of inode in bdget could fail. Hence, this patch introduces a check for bdev to prevent reference to a NULL pointer in the later part of the code. It also removes unnecessary check of bdev for fsync_bdev(). Cc: stable <stable@vger.kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Staging: zram: Fix variable dereferenced before checkRashika Kheria2016-06-051-6/+3
| | | | | | | | | | | This patch fixes the following Smatch warning in zram_drv.c- drivers/staging/zram/zram_drv.c:899 destroy_device() warn: variable dereferenced before check 'zram->disk' (see line 896) Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "staging: zram: Add auto loading of module if user opens /dev/zram."Greg Kroah-Hartman2016-06-051-1/+0
| | | | | | | | | | | | | | | | | | | This reverts commit c70bda992c12e593e411c02a52e4bd6985407539. It's incorrect, Kay writes: Please just remove it. "devname" is meant to be used for single-instance devices with a static dev_t, never for things like zramX. It will not do anything useful here, it does nothing really without a statically assigned dev_t, and it should not be used for devices of this kind anyway. Reported-by: Tom Gundersen <teg@jklm.no> Reported-by: Kay Sievers <kay@vrfy.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* zsmalloc: add more commentNitin Cupta2016-06-052-11/+64
| | | | | | | | | | This patch adds lots of comments and it will help others to review and enhance. Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* zsmalloc: add Kconfig for enabling page table methodMinchan Kim2016-06-052-15/+17
| | | | | | | | | | | | | | | | | | | Zsmalloc has two methods 1) copy-based and 2) pte based to access objects that span two pages. You can see history why we supported two approach from [1]. But it was bad choice that adding hard coding to select arch which want to use pte based method because there are lots of SoC in an architecure and they can have different cache size, CPU speed and so on so it would be better to expose it to user as selectable Kconfig option like Andrew Morton suggested. [1] https://lkml.org/lkml/2012/7/11/58 Acked-by: Nitin Gupta <ngupta@vflare.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* staging: zsmalloc: Ensure handle is never 0 on successOlav Haugan2016-06-051-4/+13
| | | | | | | | | | | | | | | | | zsmalloc encodes a handle using the pfn and an object index. On hardware platforms with physical memory starting at 0x0 the pfn can be 0. This causes the encoded handle to be 0 and is incorrectly interpreted as an allocation failure. This issue affects all current and future SoCs with physical memory starting at 0x0. All MSM8974 SoCs which includes Google Nexus 5 devices are affected. To prevent this false error we ensure that the encoded handle will not be 0 when allocation succeeds. Change-Id: I5ad31712be4dd5105ebee81fa95927039c0f6935 Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* staging: zsmalloc: access page->private by using page_private macroSunghan Suh2016-06-051-2/+2
| | | | | | | | | Change-Id: Ia09720c7787bc03c69d01874437bdc619cae8c7e Signed-off-by: Sunghan Suh <sunghan.suh@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: e842b976a88a39b447fc34bd0fcb3c0be0a1d9d9 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* staging/zsmalloc: Fixed up incorrect formatted commentsSara Bird2016-06-052-3/+3
| | | | | | | | | | | | The existing comments are using an odd style. Fixed them up to adhere to the StyleGuide. No code changes. Change-Id: I24a720787c00a79883cb268ebf1257b525655f7d Signed-off-by: Sara Bird <sara.bird.iar@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 396b7fd6f9668c04f20ee6daca3054f5c5ec1056 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* Staging: Fixes string split across lines in zsmalloc zsmalloc-mainMarlies Ruck2016-06-051-2/+1
| | | | | | | | | | | | Fixes the following checkpatch warning: WARNING: quoted string split across lines Change-Id: Ia192b2d0213de838d61f77db233169c802a4419f Signed-off-by: Marlies Ruck <marlies.ruck@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 93ad5ab50476aa7e2b33aac31f41d0efc9f729d7 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* staging: zram: Rate limit memory allocation errorsOlav Haugan2016-06-051-2/+12
| | | | | | | | | | | | | | | If an error occurs allocating memory for zram we will not be able to fullfill the request to store the page in zram. The swap subsystem still continues to try to swap out pages to zram even when this error occurs since there is currently no facility to stop the swap subsystem from swapping out during such errors. This can cause the system to be overflowed with logging errors. Reduce the amount of logging to prevent the kernel log from being filled with these error messages. Change-Id: I54b920337749ece59d9ca78fa8b29345ec7b976b Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: Change ratio to 90% for bad compressOlav Haugan2016-06-051-1/+1
| | | | | | | | | Change the ratio for determining whether or not we should store pages as uncompressed in zram. This will allow zram to fit more data since more of the pages will be stored as compressed. Change-Id: I37170cafff7e8a4cc44f1622fe52a6cbff85f218 Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: Disable allocation failure loggingOlav Haugan2016-06-051-1/+2
| | | | | | | | | Disable the logging of errors when allocations fail for zram pages. This avoid excessive logging when system is very low on memory. Change-Id: Ifabcf8f1b9c3e3717599d6a0a924f7b2061f00ea Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: don't grab mutex in zram_slot_free_noityMinchan Kim2016-06-052-3/+67
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [1] introduced down_write in zram_slot_free_notify to prevent race between zram_slot_free_notify and zram_bvec_[read|write]. The race could happen if somebody who has right permission to open swap device is reading swap device while it is used by swap in parallel. However, zram_slot_free_notify is called with holding spin_lock of swap layer so we shouldn't avoid holing mutex. Otherwise, lockdep warns it. This patch adds new list to handle free slot and workqueue so zram_slot_free_notify just registers slot index to be freed and registers the request to workqueue. If workqueue is expired, it holds mutex_lock so there is no problem any more. If any I/O is issued, zram handles pending slot-free request caused by zram_slot_free_notify right before handling issued request because workqueue wouldn't be expired yet so zram I/O request handling function can miss it. Lastly, when zram is reset, flush_work could handle all of pending free request so we shouldn't have memory leak. NOTE: If zram_slot_free_notify's kmalloc with GFP_ATOMIC would be failed, the slot will be freed when next write I/O write the slot. [1] [57ab0485, zram: use zram->lock to protect zram_free_page() in swap free notify path] * from v2 * refactoring * from v1 * totally redesign Change-Id: Ic69dce098c89bb7cb5563566b802375320b90a76 Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: a0c516cbfc7452c8cbd564525fef66d9f20b46d1 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: fix invalid memory accessMinchan Kim2016-06-051-6/+9
| | | | | | | | | | | | | | | | | | | | | | [1] tried to fix invalid memory access on zram->disk but it didn't fix properly because get_disk failed during module exit path. Actually, we don't need to reset zram->disk's capacity to zero in module exit path so that this patch introduces new argument "reset_capacity" on zram_reset_divice and it only reset it when reset_store is called. [1] 6030ea9b, zram: avoid invalid memory access in zram_exit() Change-Id: I6616ac8f82aab6d03a47f3cfb91d28a825e6e3a6 Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 2b86ab9cc29fcd435cde9378c3b9ffe8b5c76128 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* Staging: zram: zram_drv.c: Fixed Error of trailing whitespaceKumar Gaurav2016-06-051-1/+1
| | | | | | | | | | | Fixed by removing trailing whitespace Change-Id: If43b8acf92d4c504c443c8e4c7995de3e410aca0 Signed-off-by: Kumar Gaurav <kumargauravgupta3@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: a539c72a195c081d950475c2945cb82d80be9b66 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: prevent data loss in error cases of function zram_bvec_write()Sunghan Suh2016-06-051-8/+9
| | | | | | | | | | | | | | | | | In function zram_bvec_write(), previous data at the index is already freed by function zram_free_page(). When failed to compress or zs_malloc, there is no way to restore old data. Therefore, free previous data when it's about to update. Also, no need to check whether table is not empty outside of function zram_free_page(), because the function properly checks inside. Change-Id: I8cb3daf146a99d3b5999c7a42e5e2a260f4c3a48 Signed-off-by: Sunghan Suh <sunghan.suh@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: f40ac2ae1b506484dd9261a24bbf3e86b2206ff8 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* staging: zram: Add auto loading of module if user opens /dev/zram.Konrad Rzeszutek Wilk2016-06-051-0/+1
| | | | | | | | | | | | | | | Greg spotted that said driver is not subscribing to the automagic mechanism of auto-loading if a user tries to open /dev/zram. This fixes it. Change-Id: Ib169a11a1a2717967350015d58d77f431ab5b973 CC: Minchan Kim <minchan@kernel.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: c70bda992c12e593e411c02a52e4bd6985407539 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* staging: zram: protect zram_reset_device() callSergey Senozhatsky2016-06-051-1/+5
| | | | | | | | | | | | | | Commit 9b3bb7abcdf2df0f1b2657e6cbc9d06bc2b3b36f (remove zram_sysfs file (v2)) accidentally made zram_reset_device() racy. Protect zram_reset_device() call with zram->lock. Change-Id: I93ce19f9b262584f4ef805dce5ed4de9b3968a30 Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Jerome Marchand <jmarchand@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 644d478793c6594277f8ae76954da4ace7ac6f96 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: allow request end to coincide with disksizeSergey Senozhatsky2016-06-051-1/+1
| | | | | | | | | | | | | | | | | Pass valid_io_request() checks if request end coincides with disksize (end equals bound), only fail if we attempt to read beyond the bound. mkfs.ext2 produces numerous errors: [ 2164.632747] quiet_error: 1 callbacks suppressed [ 2164.633260] Buffer I/O error on device zram0, logical block 153599 [ 2164.633265] lost page write due to I/O error on zram0 Change-Id: I71f9f52ec11897d0462d3ff54a853040faf36dcd Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 75c7caf5a052ffd8db3312fa7864ee2d142890c4 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: remove zram_sysfs file (v2)Sergey Senozhatsky2016-06-054-387/+350
| | | | | | | | | | | | | | | | | | | Move zram sysfs code to zram drv and remove zram_sysfs.c file. This gives ability to make static a number of previously exported zram functions, used from zram sysfs, e.g. internal zram zram_meta_alloc/free(). We also can drop zram_drv wrapper functions, used from zram sysfs: e.g. zram_reset_device()/__zram_reset_device() pair. v2: as suggested by Greg K-H, move MODULE description to the bottom of the file. Change-Id: I2338b812daa1fef0ec7015082ecccb8ec6c84b8f Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 9b3bb7abcdf2df0f1b2657e6cbc9d06bc2b3b36f Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: use atomic64_xxx() to replace zram_stat64_xxx()Jiang Liu2016-06-053-53/+24
| | | | | | | | | | | | | | | | Use atomic64_xxx() to replace open-coded zram_stat64_xxx(). Some architectures have native support of atomic64 operations, so we can get rid of the spin_lock() in zram_stat64_xxx(). On the other hand, for platforms use generic version of atomic64 implement, it may cause an extra save/restore of the interrupt flag. So it's a tradeoff. Change-Id: Ic1e5f79328b998ec2d0b571851199dfd2d5560a6 Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: da5cc7d338f97886ebf35be92995460289379b73 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: simplify and optimize dev_to_zram()Jiang Liu2016-06-051-11/+2
| | | | | | | | | | | | Simplify and optimize dev_to_zram() without walking the zram_devices array. Change-Id: I7d2031baabfd880ee8479abf3657358cd7db57cb Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 80de574dca050b734d8413a98a983fba3d06240b Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: protect sysfs handler from invalid memory accessJiang Liu2016-06-051-0/+2
| | | | | | | | | | | | | | | | | | | | | Use zram->init_lock to protect access to zram->meta, otherwise it may cause invalid memory access if zram->meta has been freed by zram_reset_device(). This issue may be triggered by: Thread 1: while true; do cat mem_used_total; done Thread 2: while true; do echo 8M > disksize; echo 1 > reset; done Change-Id: Id6105b37f083cfd41d9885a251aeef61f72bb92f Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 5863e10b441e7ea4b492f930f1be180a97d026f3 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: optimize memory operations with clear_page()/copy_page()Jiang Liu2016-06-051-11/+16
| | | | | | | | | | | | | | Some architectures provides architecture-specific, optimized version of clear_page()/copy_page(), which may have better performance than memset()/memcpy(). So use clear_page()/copy_page() to optimize zram performance if possible. Change-Id: I6b4530f16d45d0005ff498f48b03f727e73044cb Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 42e99bd975fdd24d2bf1a24ebb8b0b42bab8ba65 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: kill unused zram_get_num_devices()Jiang Liu2016-06-052-8/+1
| | | | | | | | | | | | Now there's no caller of zram_get_num_devices(), so kill it. And change zram_devices to static because it's only used in zram_drv.c. Change-Id: Iaf686cf9ae9673325ba481f001df689cedfa2c66 Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 0f0e3ba346c8d8d2cb409b157df79805931a1c2c Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: avoid access beyond the zram deviceJiang Liu2016-06-051-5/+12
| | | | | | | | | | | | | | | | Function valid_io_request() should verify the entire request are within the zram device address range. Otherwise it may cause invalid memory access when accessing/modifying zram->meta->table[index] because the 'index' is out of range. Then it may access non-exist memory, randomly modify memory belong to other subsystems, which is hard to track down. Change-Id: Ic6630e8ed5945b7c0f4f63ccc378f9780dfc4567 Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 12a7ad3b810e77137d0caf97a6dd97591e075b30 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: avoid double free in function zram_bvec_write()Jiang Liu2016-06-051-2/+0
| | | | | | | | | | | | | | When doing a patial write and the whole page is filled with zero, zram_bvec_write() will free uncmem twice. Change-Id: I233f44846f29dbf11e05d277506137bc7f11bbd9 Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 65c484609a3b25c35e4edcd5f2c38f98f5226093 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: destroy all devices on error recovery path in zram_init()Jiang Liu2016-06-051-6/+9
| | | | | | | | | | | | | | | | On error recovery path of zram_init(), it leaks the zram device object causing the failure. So change create_device() to free allocated resources on error path. Change-Id: Ia8508ab9aad3201c6fc12634b8e134d78d7d1423 Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 39a9b8ac9333e4268ecff7da6c9d1ab3823ff243 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: use zram->lock to protect zram_free_page() in swap free notify pathJiang Liu2016-06-052-2/+5
| | | | | | | | | | | | | | | | | | | | | | | zram_slot_free_notify() is free-running without any protection from concurrent operations. So there are race conditions between zram_bvec_read()/zram_bvec_write() and zram_slot_free_notify(), and possible consequences include: 1) Trigger BUG_ON(!handle) on zram_bvec_write() side. 2) Access to freed pages on zram_bvec_read() side. 3) Break some fields (bad_compress, good_compress, pages_stored) in zram->stats if the swap layer makes concurrently call to zram_slot_free_notify(). So enhance zram_slot_free_notify() to acquire writer lock on zram->lock before calling zram_free_page(). Change-Id: I805806668d91aaf4c8be7359cb1fd9c877c41f72 Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 57ab048532c0d975538cebd4456491b5c34248f4 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* zram: avoid invalid memory access in zram_exit()Jiang Liu2016-06-051-0/+2
| | | | | | | | | | | | | | | | | | | | | Memory for zram->disk object may have already been freed after returning from destroy_device(zram), then it's unsafe for zram_reset_device(zram) to access zram->disk again. We can't solve this bug by flipping the order of destroy_device(zram) and zram_reset_device(zram), that will cause deadlock issues to the zram sysfs handler. So fix it by holding an extra reference to zram->disk before calling destroy_device(zram). Change-Id: I1022247325ab2ec31a094587e13d5c4c759e5a36 Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Git-commit: 6030ea9b35971a4200062f010341ab832e878ac9 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
generated by cgit v1.1 at 2025-01-12 22:52:17 +0000