Merge remote-tracking branch 'common/android-3.0' into android-samsung-30-wip-mergedown

* common/android-3.0: (1178 commits)
  cpufreq: interactive: remove unused target_validate_time_in_idle
  cpufreq: interactive: Boost frequency on touchscreen input
  cpufreq: Separate speed target revalidate time and initial set time
  cpufreq: interactive: based hispeed bump on target freq, not actual
  cpufreq: interactive: adjust code and documentation to match
  cpufreq: interactive: configurable delay before raising above hispeed
  sync: add poll support
  sw_sync: add fill_driver_data support
  sync: add ioctl to get fence data
  sw_sync: add debug support
  sync: add debugfs support
  sync: add timestamps to sync_pts
  sw_sync: add cpu based sync driver
  sync: Add synchronization framework
  Linux 3.0.28
  Bluetooth: Fix l2cap conn failures for ssp devices
  TOMOYO: Fix mount flags checking order.
  iommu/amd: Make sure IOMMU interrupts are re-enabled on resume
  cred: copy_process() should clear child->replacement_session_keyring
  ASoC: ak4642: fixup: mute needs +1 step
  ...

Conflicts:
	mm/compaction.c

Change-Id: I3dc59225d2435eddbed0c639155179e580891ac8
Signed-off-by: JP Abgrall <jpa@google.com>

1 files changed, 28 insertions, 6 deletions

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index 7f782af..b679198 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -309,7 +309,19 @@ xfs_file_aio_read(
 	if (XFS_FORCED_SHUTDOWN(mp))
 		return -EIO;
 
-	if (unlikely(ioflags & IO_ISDIRECT)) {
+	/*
+	 * Locking is a bit tricky here. If we take an exclusive lock
+	 * for direct IO, we effectively serialise all new concurrent
+	 * read IO to this file and block it behind IO that is currently in
+	 * progress because IO in progress holds the IO lock shared. We only
+	 * need to hold the lock exclusive to blow away the page cache, so
+	 * only take lock exclusively if the page cache needs invalidation.
+	 * This allows the normal direct IO case of no page cache pages to
+	 * proceeed concurrently without serialisation.
+	 */
+	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
+	if ((ioflags & IO_ISDIRECT) && inode->i_mapping->nrpages) {
+		xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
 		xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);
 
 		if (inode->i_mapping->nrpages) {
@@ -322,8 +334,7 @@ xfs_file_aio_read(
 			}
 		}
 		xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
-	} else
-		xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
+	}
 
 	trace_xfs_file_read(ip, size, iocb->ki_pos, ioflags);
 
@@ -658,6 +669,7 @@ xfs_file_aio_write_checks(
 	xfs_fsize_t		new_size;
 	int			error = 0;
 
+	xfs_rw_ilock(ip, XFS_ILOCK_EXCL);
 	error = generic_write_checks(file, pos, count, S_ISBLK(inode->i_mode));
 	if (error) {
 		xfs_rw_iunlock(ip, XFS_ILOCK_EXCL | *iolock);
@@ -749,14 +761,24 @@ xfs_file_dio_aio_write(
 		*iolock = XFS_IOLOCK_EXCL;
 	else
 		*iolock = XFS_IOLOCK_SHARED;
-	xfs_rw_ilock(ip, XFS_ILOCK_EXCL | *iolock);
+	xfs_rw_ilock(ip, *iolock);
 
 	ret = xfs_file_aio_write_checks(file, &pos, &count, iolock);
 	if (ret)
 		return ret;
 
+	/*
+	 * Recheck if there are cached pages that need invalidate after we got
+	 * the iolock to protect against other threads adding new pages while
+	 * we were waiting for the iolock.
+	 */
+	if (mapping->nrpages && *iolock == XFS_IOLOCK_SHARED) {
+		xfs_rw_iunlock(ip, *iolock);
+		*iolock = XFS_IOLOCK_EXCL;
+		xfs_rw_ilock(ip, *iolock);
+	}
+
 	if (mapping->nrpages) {
-		WARN_ON(*iolock != XFS_IOLOCK_EXCL);
 		ret = -xfs_flushinval_pages(ip, (pos & PAGE_CACHE_MASK), -1,
 							FI_REMAPF_LOCKED);
 		if (ret)
@@ -801,7 +823,7 @@ xfs_file_buffered_aio_write(
 	size_t			count = ocount;
 
 	*iolock = XFS_IOLOCK_EXCL;
-	xfs_rw_ilock(ip, XFS_ILOCK_EXCL | *iolock);
+	xfs_rw_ilock(ip, *iolock);
 
 	ret = xfs_file_aio_write_checks(file, &pos, &count, iolock);
 	if (ret)