From 6613c5e8603bc41741487828f48c6a4d701f7814 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Mon, 14 Dec 2009 18:00:11 -0800 Subject: uml: convert to seq_file/proc_fops Convert code away from ->read_proc/->write_proc interfaces. Switch to proc_create()/proc_create_data() which make addition of proc entries reliable wrt NULL ->proc_fops, NULL ->data and so on. Problem with ->read_proc et al is described here commit 786d7e1612f0b0adb6046f19b906609e4fe8b1ba "Fix rmmod/read/write races in /proc entries" Signed-off-by: Alexey Dobriyan Cc: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/drivers/mconsole_kern.c | 14 ++++++++------ arch/um/drivers/ubd_kern.c | 36 ++++++++++++++++++------------------ 2 files changed, 26 insertions(+), 24 deletions(-) (limited to 'arch/um/drivers') diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index e14629c..f0fa47f 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -833,8 +833,8 @@ static int __init mconsole_init(void) __initcall(mconsole_init); -static int write_proc_mconsole(struct file *file, const char __user *buffer, - unsigned long count, void *data) +static ssize_t mconsole_proc_write(struct file *file, + const char __user *buffer, size_t count, loff_t *pos) { char *buf; @@ -855,6 +855,11 @@ static int write_proc_mconsole(struct file *file, const char __user *buffer, return count; } +static const struct file_operations mconsole_proc_fops = { + .owner = THIS_MODULE, + .write = mconsole_proc_write, +}; + static int create_proc_mconsole(void) { struct proc_dir_entry *ent; @@ -862,15 +867,12 @@ static int create_proc_mconsole(void) if (notify_socket == NULL) return 0; - ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL); + ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops); if (ent == NULL) { printk(KERN_INFO "create_proc_mconsole : create_proc_entry " "failed\n"); return 0; } - - ent->read_proc = NULL; - ent->write_proc = write_proc_mconsole; return 0; } diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index 635d16d..5ff5546 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -27,6 +27,7 @@ #include "linux/init.h" #include "linux/cdrom.h" #include "linux/proc_fs.h" +#include "linux/seq_file.h" #include "linux/ctype.h" #include "linux/capability.h" #include "linux/mm.h" @@ -200,23 +201,25 @@ static void make_proc_ide(void) proc_ide = proc_mkdir("ide0", proc_ide_root); } -static int proc_ide_read_media(char *page, char **start, off_t off, int count, - int *eof, void *data) +static int fake_ide_media_proc_show(struct seq_file *m, void *v) { - int len; - - strcpy(page, "disk\n"); - len = strlen("disk\n"); - len -= off; - if (len < count){ - *eof = 1; - if (len <= 0) return 0; - } - else len = count; - *start = page + off; - return len; + seq_puts(m, "disk\n"); + return 0; +} + +static int fake_ide_media_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, fake_ide_media_proc_show, NULL); } +static const struct file_operations fake_ide_media_proc_fops = { + .owner = THIS_MODULE, + .open = fake_ide_media_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + static void make_ide_entries(const char *dev_name) { struct proc_dir_entry *dir, *ent; @@ -227,11 +230,8 @@ static void make_ide_entries(const char *dev_name) dir = proc_mkdir(dev_name, proc_ide); if(!dir) return; - ent = create_proc_entry("media", S_IFREG|S_IRUGO, dir); + ent = proc_create("media", S_IRUGO, dir, &fake_ide_media_proc_fops); if(!ent) return; - ent->data = NULL; - ent->read_proc = proc_ide_read_media; - ent->write_proc = NULL; snprintf(name, sizeof(name), "ide0/%s", dev_name); proc_symlink(dev_name, proc_ide_root, name); } -- cgit v1.1 From e7d2860b690d4f3bed6824757c540579638e3d1e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Goddard=20Rosa?= Date: Mon, 14 Dec 2009 18:01:06 -0800 Subject: tree-wide: convert open calls to remove spaces to skip_spaces() lib function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa Cc: Julia Lawall Cc: Martin Schwidefsky Cc: Jeff Dike Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Richard Purdie Cc: Neil Brown Cc: Kyle McMartin Cc: Henrique de Moraes Holschuh Cc: David Howells Cc: Cc: Samuel Ortiz Cc: Patrick McHardy Cc: Takashi Iwai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/drivers/mconsole_kern.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'arch/um/drivers') diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index f0fa47f..5106924 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -6,6 +6,7 @@ #include #include +#include #include #include #include @@ -131,7 +132,7 @@ void mconsole_proc(struct mc_request *req) char *ptr = req->request.data, *buf; ptr += strlen("proc"); - while (isspace(*ptr)) ptr++; + ptr = skip_spaces(ptr); proc = get_fs_type("proc"); if (proc == NULL) { @@ -212,8 +213,7 @@ void mconsole_proc(struct mc_request *req) char *ptr = req->request.data; ptr += strlen("proc"); - while (isspace(*ptr)) - ptr++; + ptr = skip_spaces(ptr); snprintf(path, sizeof(path), "/proc/%s", ptr); fd = sys_open(path, 0, 0); @@ -560,8 +560,7 @@ void mconsole_config(struct mc_request *req) int err; ptr += strlen("config"); - while (isspace(*ptr)) - ptr++; + ptr = skip_spaces(ptr); dev = mconsole_find_dev(ptr); if (dev == NULL) { mconsole_reply(req, "Bad configuration option", 1, 0); @@ -588,7 +587,7 @@ void mconsole_remove(struct mc_request *req) int err, start, end, n; ptr += strlen("remove"); - while (isspace(*ptr)) ptr++; + ptr = skip_spaces(ptr); dev = mconsole_find_dev(ptr); if (dev == NULL) { mconsole_reply(req, "Bad remove option", 1, 0); @@ -712,7 +711,7 @@ void mconsole_sysrq(struct mc_request *req) char *ptr = req->request.data; ptr += strlen("sysrq"); - while (isspace(*ptr)) ptr++; + ptr = skip_spaces(ptr); /* * With 'b', the system will shut down without a chance to reply, @@ -757,8 +756,7 @@ void mconsole_stack(struct mc_request *req) */ ptr += strlen("stack"); - while (isspace(*ptr)) - ptr++; + ptr = skip_spaces(ptr); /* * Should really check for multiple pids or reject bad args here -- cgit v1.1 From 4ecf09fd3a7c8858198875171b684c73338fad83 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 24 Dec 2009 00:44:44 -0500 Subject: Unrot uml mconsole a bit Signed-off-by: Al Viro --- arch/um/drivers/mconsole_kern.c | 49 +++++++++++++++-------------------------- 1 file changed, 18 insertions(+), 31 deletions(-) (limited to 'arch/um/drivers') diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index 5106924..3b3c366 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -125,50 +125,36 @@ void mconsole_log(struct mc_request *req) void mconsole_proc(struct mc_request *req) { struct nameidata nd; - struct file_system_type *proc; - struct super_block *super; + struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt; struct file *file; int n, err; char *ptr = req->request.data, *buf; + mm_segment_t old_fs = get_fs(); ptr += strlen("proc"); ptr = skip_spaces(ptr); - proc = get_fs_type("proc"); - if (proc == NULL) { - mconsole_reply(req, "procfs not registered", 1, 0); + err = vfs_path_lookup(mnt->mnt_root, mnt, ptr, LOOKUP_FOLLOW, &nd); + if (err) { + mconsole_reply(req, "Failed to look up file", 1, 0); goto out; } - super = (*proc->get_sb)(proc, 0, NULL, NULL); - put_filesystem(proc); - if (super == NULL) { - mconsole_reply(req, "Failed to get procfs superblock", 1, 0); + err = may_open(&nd.path, MAY_READ, FMODE_READ); + if (result) { + mconsole_reply(req, "Failed to open file", 1, 0); + path_put(&nd.path); goto out; } - up_write(&super->s_umount); - - nd.path.dentry = super->s_root; - nd.path.mnt = NULL; - nd.flags = O_RDONLY + 1; - nd.last_type = LAST_ROOT; - - /* START: it was experienced that the stability problems are closed - * if commenting out these two calls + the below read cycle. To - * make UML crash again, it was enough to readd either one.*/ - err = link_path_walk(ptr, &nd); - if (err) { - mconsole_reply(req, "Failed to look up file", 1, 0); - goto out_kill; - } file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY, current_cred()); + err = PTR_ERR(file); if (IS_ERR(file)) { mconsole_reply(req, "Failed to open file", 1, 0); - goto out_kill; + path_put(&nd.path); + goto out; } - /*END*/ buf = kmalloc(PAGE_SIZE, GFP_KERNEL); if (buf == NULL) { @@ -176,10 +162,13 @@ void mconsole_proc(struct mc_request *req) goto out_fput; } - if ((file->f_op != NULL) && (file->f_op->read != NULL)) { + if (file->f_op->read) { do { - n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1, - &file->f_pos); + loff_t pos; + set_fs(KERNEL_DS); + n = vfs_read(file, buf, PAGE_SIZE - 1, &pos); + file_pos_write(file, pos); + set_fs(old_fs); if (n >= 0) { buf[n] = '\0'; mconsole_reply(req, buf, 0, (n > 0)); @@ -197,8 +186,6 @@ void mconsole_proc(struct mc_request *req) kfree(buf); out_fput: fput(file); - out_kill: - deactivate_super(super); out: ; } #endif -- cgit v1.1