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authorJonathan Corbet <corbet@lwn.net>2009-02-06 15:25:24 -0700
committerJonathan Corbet <corbet@lwn.net>2009-03-16 08:32:27 -0600
commitdb1dd4d376134eba0e08af523b61cc566a4ea1cd (patch)
tree8882c673abbaa5713511b7046493fa862b9140d1 /drivers/usb/gadget
parent684999149002dd046269666a390458e0acb38280 (diff)
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/usb/gadget')
-rw-r--r--drivers/usb/gadget/file_storage.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c
index 1ab9dac7e12..33bb76cef33 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;