| Message ID | 1509195507-29037-2-git-send-email-houtao1@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, 28 Oct 2017, Hou Tao wrote: >Remove the global epmutex from ep_free() and eventpoll_release_file(). >In the later patches, we will add locks with a smaller granularity >to serve the same purposes of epmutex. > >Signed-off-by: Hou Tao <houtao1@huawei.com> >--- > fs/eventpoll.c | 4 ---- > 1 file changed, 4 deletions(-) > >diff --git a/fs/eventpoll.c b/fs/eventpoll.c >index 2fabd19..26ab0c5 100644 >--- a/fs/eventpoll.c >+++ b/fs/eventpoll.c >@@ -835,7 +835,6 @@ static void ep_free(struct eventpoll *ep) > * anymore. The only hit might come from eventpoll_release_file() but > * holding "epmutex" is sufficient here. > */ ^^ What about this comment (and the equivalent one in eventpoll_release_file()? >- mutex_lock(&epmutex); ...even if you fix it in a later patch, this patch breaks bisection. Now we just race between ep_free() and eventpoll_release_file(). This patch should be folded in, no? Thanks, Davidlohr
Hi, On 2017/10/28 21:58, Davidlohr Bueso wrote: > On Sat, 28 Oct 2017, Hou Tao wrote: > >> Remove the global epmutex from ep_free() and eventpoll_release_file(). >> In the later patches, we will add locks with a smaller granularity >> to serve the same purposes of epmutex. >> >> Signed-off-by: Hou Tao <houtao1@huawei.com> >> --- >> fs/eventpoll.c | 4 ---- >> 1 file changed, 4 deletions(-) >> >> diff --git a/fs/eventpoll.c b/fs/eventpoll.c >> index 2fabd19..26ab0c5 100644 >> --- a/fs/eventpoll.c >> +++ b/fs/eventpoll.c >> @@ -835,7 +835,6 @@ static void ep_free(struct eventpoll *ep) >> * anymore. The only hit might come from eventpoll_release_file() but >> * holding "epmutex" is sufficient here. >> */ > ^^ > What about this comment (and the equivalent one in eventpoll_release_file()? > >> - mutex_lock(&epmutex); > Thanks for your reminder. I will fix the related comments in a v1 patchset. > ...even if you fix it in a later patch, this patch breaks bisection. Now > we just race between ep_free() and eventpoll_release_file(). This patch > should be folded in, no? Yes, the patchset should be squashed into one patch, however it will be difficult to explain the purpose of these modifications, so I break them into little pieces, and hoped that these little patches can explain the reason why the modification is needed in a cleaner way. It also will be fixed in v1 patch. Regards, Tao > Thanks, > Davidlohr > > . >
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 2fabd19..26ab0c5 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -835,7 +835,6 @@ static void ep_free(struct eventpoll *ep) * anymore. The only hit might come from eventpoll_release_file() but * holding "epmutex" is sufficient here. */ - mutex_lock(&epmutex); /* * Walks through the whole tree by unregistering poll callbacks. @@ -863,7 +862,6 @@ static void ep_free(struct eventpoll *ep) } mutex_unlock(&ep->mtx); - mutex_unlock(&epmutex); mutex_destroy(&ep->mtx); free_uid(ep->user); wakeup_source_unregister(ep->ws); @@ -1013,14 +1011,12 @@ void eventpoll_release_file(struct file *file) * * Besides, ep_remove() acquires the lock, so we can't hold it here. */ - mutex_lock(&epmutex); list_for_each_entry_safe(epi, next, &file->f_ep_links, fllink) { ep = epi->ep; mutex_lock_nested(&ep->mtx, 0); ep_remove(ep, epi); mutex_unlock(&ep->mtx); } - mutex_unlock(&epmutex); } static int ep_alloc(struct eventpoll **pep)
Remove the global epmutex from ep_free() and eventpoll_release_file(). In the later patches, we will add locks with a smaller granularity to serve the same purposes of epmutex. Signed-off-by: Hou Tao <houtao1@huawei.com> --- fs/eventpoll.c | 4 ---- 1 file changed, 4 deletions(-)