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| author | Jonathan Corbet <corbet@lwn.net> | 2009-02-06 15:25:24 -0700 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2009-03-16 08:32:27 -0600 |
| commit | db1dd4d376134eba0e08af523b61cc566a4ea1cd (patch) | |
| tree | 8882c673abbaa5713511b7046493fa862b9140d1 /drivers | |
| parent | 684999149002dd046269666a390458e0acb38280 (diff) | |
| download | linux-db1dd4d376134eba0e08af523b61cc566a4ea1cd.tar.gz linux-db1dd4d376134eba0e08af523b61cc566a4ea1cd.tar.bz2 linux-db1dd4d376134eba0e08af523b61cc566a4ea1cd.zip | |
Use f_lock to protect f_flags
Traditionally, changes to struct file->f_flags have been done under BKL
protection, or with no protection at all. This patch causes all f_flags
changes after file open/creation time to be done under protection of
f_lock. This allows the removal of some BKL usage and fixes a number of
longstanding (if microscopic) races.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/char/tty_io.c | 5 | ||||
| -rw-r--r-- | drivers/usb/gadget/file_storage.c | 7 |
2 files changed, 8 insertions, 4 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index bc84e125c6bc..224f271d8cbe 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2162,13 +2162,12 @@ static int fionbio(struct file *file, int __user *p) if (get_user(nonblock, p)) return -EFAULT; - /* file->f_flags is still BKL protected in the fs layer - vomit */ - lock_kernel(); + spin_lock(&file->f_lock); if (nonblock) file->f_flags |= O_NONBLOCK; else file->f_flags &= ~O_NONBLOCK; - unlock_kernel(); + spin_unlock(&file->f_lock); return 0; } diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c index 1ab9dac7e12d..33bb76cef33c 100644 --- a/drivers/usb/gadget/file_storage.c +++ b/drivers/usb/gadget/file_storage.c @@ -1711,7 +1711,9 @@ static int do_write(struct fsg_dev *fsg) curlun->sense_data = SS_WRITE_PROTECTED; return -EINVAL; } + spin_lock(&curlun->filp->f_lock); curlun->filp->f_flags &= ~O_SYNC; // Default is not to wait + spin_unlock(&curlun->filp->f_lock); /* Get the starting Logical Block Address and check that it's * not too big */ @@ -1728,8 +1730,11 @@ static int do_write(struct fsg_dev *fsg) curlun->sense_data = SS_INVALID_FIELD_IN_CDB; return -EINVAL; } - if (fsg->cmnd[1] & 0x08) // FUA + if (fsg->cmnd[1] & 0x08) { // FUA + spin_lock(&curlun->filp->f_lock); curlun->filp->f_flags |= O_SYNC; + spin_unlock(&curlun->filp->f_lock); + } } if (lba >= curlun->num_sectors) { curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE; |