Revision 4cdd2ad78098244c1bc9ec4374ea1c225fd1cd6f authored by Mike Snitzer on 13 May 2014, 17:49:39 UTC, committed by Mike Snitzer on 14 May 2014, 20:12:17 UTC
Commit 3e9f1be1b40 ("dm mpath: remove process_queued_ios()") did not
consistently take the multipath device's spinlock (m->lock) before
calling dm_table_run_md_queue_async() -- which takes the q->queue_lock.
Found with code inspection using hint from reported lockdep warning.
Reported-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1 parent 85ad643
iovec.c
#include <linux/uaccess.h>
#include <linux/export.h>
#include <linux/uio.h>
/*
* Copy iovec to kernel. Returns -EFAULT on error.
*
* Note: this modifies the original iovec.
*/
int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
{
while (len > 0) {
if (iov->iov_len) {
int copy = min_t(unsigned int, len, iov->iov_len);
if (copy_from_user(kdata, iov->iov_base, copy))
return -EFAULT;
len -= copy;
kdata += copy;
iov->iov_base += copy;
iov->iov_len -= copy;
}
iov++;
}
return 0;
}
EXPORT_SYMBOL(memcpy_fromiovec);
/*
* Copy kernel to iovec. Returns -EFAULT on error.
*
* Note: this modifies the original iovec.
*/
int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
{
while (len > 0) {
if (iov->iov_len) {
int copy = min_t(unsigned int, iov->iov_len, len);
if (copy_to_user(iov->iov_base, kdata, copy))
return -EFAULT;
kdata += copy;
len -= copy;
iov->iov_len -= copy;
iov->iov_base += copy;
}
iov++;
}
return 0;
}
EXPORT_SYMBOL(memcpy_toiovec);
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