* [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page @ 2019-02-16 8:46 ` Gao Xiang 0 siblings, 0 replies; 10+ messages in thread From: Gao Xiang @ 2019-02-16 8:46 UTC (permalink / raw) page_private(page) cannot be changed if page lock is taken. Besides, the corresponding workgroup won't be freed if the page is already protected by page lock, therefore no need to take rcu read lock. Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com> --- drivers/staging/erofs/unzip_vle.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c index 2b5951f233db..a127d8db76d8 100644 --- a/drivers/staging/erofs/unzip_vle.c +++ b/drivers/staging/erofs/unzip_vle.c @@ -238,14 +238,9 @@ int erofs_try_to_free_cached_page(struct address_space *mapping, { struct erofs_sb_info *const sbi = EROFS_SB(mapping->host->i_sb); const unsigned int clusterpages = erofs_clusterpages(sbi); - - struct z_erofs_vle_workgroup *grp; + struct z_erofs_vle_workgroup *const grp = (void *)page_private(page); int ret = 0; /* 0 - busy */ - /* prevent the workgroup from being freed */ - rcu_read_lock(); - grp = (void *)page_private(page); - if (erofs_workgroup_try_to_freeze(&grp->obj, 1)) { unsigned int i; @@ -257,12 +252,11 @@ int erofs_try_to_free_cached_page(struct address_space *mapping, } } erofs_workgroup_unfreeze(&grp->obj, 1); - } - rcu_read_unlock(); - if (ret) { - ClearPagePrivate(page); - put_page(page); + if (ret) { + ClearPagePrivate(page); + put_page(page); + } } return ret; } -- 2.14.4 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page @ 2019-02-16 8:46 ` Gao Xiang 0 siblings, 0 replies; 10+ messages in thread From: Gao Xiang @ 2019-02-16 8:46 UTC (permalink / raw) To: Chao Yu, Greg Kroah-Hartman, devel Cc: LKML, linux-erofs, Chao Yu, Miao Xie, weidu.du, Fang Wei, Gao Xiang page_private(page) cannot be changed if page lock is taken. Besides, the corresponding workgroup won't be freed if the page is already protected by page lock, therefore no need to take rcu read lock. Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> --- drivers/staging/erofs/unzip_vle.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c index 2b5951f233db..a127d8db76d8 100644 --- a/drivers/staging/erofs/unzip_vle.c +++ b/drivers/staging/erofs/unzip_vle.c @@ -238,14 +238,9 @@ int erofs_try_to_free_cached_page(struct address_space *mapping, { struct erofs_sb_info *const sbi = EROFS_SB(mapping->host->i_sb); const unsigned int clusterpages = erofs_clusterpages(sbi); - - struct z_erofs_vle_workgroup *grp; + struct z_erofs_vle_workgroup *const grp = (void *)page_private(page); int ret = 0; /* 0 - busy */ - /* prevent the workgroup from being freed */ - rcu_read_lock(); - grp = (void *)page_private(page); - if (erofs_workgroup_try_to_freeze(&grp->obj, 1)) { unsigned int i; @@ -257,12 +252,11 @@ int erofs_try_to_free_cached_page(struct address_space *mapping, } } erofs_workgroup_unfreeze(&grp->obj, 1); - } - rcu_read_unlock(); - if (ret) { - ClearPagePrivate(page); - put_page(page); + if (ret) { + ClearPagePrivate(page); + put_page(page); + } } return ret; } -- 2.14.4 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page 2019-02-16 8:46 ` Gao Xiang @ 2019-02-20 1:26 ` Chao Yu -1 siblings, 0 replies; 10+ messages in thread From: Chao Yu @ 2019-02-20 1:26 UTC (permalink / raw) On 2019/2/16 16:46, Gao Xiang wrote: > page_private(page) cannot be changed if page lock is taken. > > Besides, the corresponding workgroup won't be freed > if the page is already protected by page lock, therefore > no need to take rcu read lock. > > Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com> Reviewed-by: Chao Yu <yuchao0 at huawei.com> Thanks, ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page @ 2019-02-20 1:26 ` Chao Yu 0 siblings, 0 replies; 10+ messages in thread From: Chao Yu @ 2019-02-20 1:26 UTC (permalink / raw) To: Gao Xiang, Greg Kroah-Hartman, devel Cc: LKML, linux-erofs, Chao Yu, Miao Xie, weidu.du, Fang Wei On 2019/2/16 16:46, Gao Xiang wrote: > page_private(page) cannot be changed if page lock is taken. > > Besides, the corresponding workgroup won't be freed > if the page is already protected by page lock, therefore > no need to take rcu read lock. > > Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Thanks, ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page 2019-02-16 8:46 ` Gao Xiang @ 2019-02-20 2:38 ` Gao Xiang -1 siblings, 0 replies; 10+ messages in thread From: Gao Xiang @ 2019-02-20 2:38 UTC (permalink / raw) Hi Greg, Could you consider take some time on these two patches for linux-5.1-rc1? 1) staging: erofs: fix race of initializing xattrs of a inode at the same time 2) staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page It will be of great help, especially patch 1 (it could cause potential memleak in the race condition without it). If something (eg, resend these patches in a new patchset) is needed, I'm happy to do that. :) Thanks, Gao Xiang On 2019/2/16 16:46, Gao Xiang wrote: > page_private(page) cannot be changed if page lock is taken. > > Besides, the corresponding workgroup won't be freed > if the page is already protected by page lock, therefore > no need to take rcu read lock. > > Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com> > --- > drivers/staging/erofs/unzip_vle.c | 16 +++++----------- > 1 file changed, 5 insertions(+), 11 deletions(-) > > diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c > index 2b5951f233db..a127d8db76d8 100644 > --- a/drivers/staging/erofs/unzip_vle.c > +++ b/drivers/staging/erofs/unzip_vle.c > @@ -238,14 +238,9 @@ int erofs_try_to_free_cached_page(struct address_space *mapping, > { > struct erofs_sb_info *const sbi = EROFS_SB(mapping->host->i_sb); > const unsigned int clusterpages = erofs_clusterpages(sbi); > - > - struct z_erofs_vle_workgroup *grp; > + struct z_erofs_vle_workgroup *const grp = (void *)page_private(page); > int ret = 0; /* 0 - busy */ > > - /* prevent the workgroup from being freed */ > - rcu_read_lock(); > - grp = (void *)page_private(page); > - > if (erofs_workgroup_try_to_freeze(&grp->obj, 1)) { > unsigned int i; > > @@ -257,12 +252,11 @@ int erofs_try_to_free_cached_page(struct address_space *mapping, > } > } > erofs_workgroup_unfreeze(&grp->obj, 1); > - } > - rcu_read_unlock(); > > - if (ret) { > - ClearPagePrivate(page); > - put_page(page); > + if (ret) { > + ClearPagePrivate(page); > + put_page(page); > + } > } > return ret; > } > ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page @ 2019-02-20 2:38 ` Gao Xiang 0 siblings, 0 replies; 10+ messages in thread From: Gao Xiang @ 2019-02-20 2:38 UTC (permalink / raw) To: Greg Kroah-Hartman Cc: Chao Yu, devel, LKML, linux-erofs, Chao Yu, Miao Xie, weidu.du, Fang Wei Hi Greg, Could you consider take some time on these two patches for linux-5.1-rc1? 1) staging: erofs: fix race of initializing xattrs of a inode at the same time 2) staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page It will be of great help, especially patch 1 (it could cause potential memleak in the race condition without it). If something (eg, resend these patches in a new patchset) is needed, I'm happy to do that. :) Thanks, Gao Xiang On 2019/2/16 16:46, Gao Xiang wrote: > page_private(page) cannot be changed if page lock is taken. > > Besides, the corresponding workgroup won't be freed > if the page is already protected by page lock, therefore > no need to take rcu read lock. > > Signed-off-by: Gao Xiang <gaoxiang25@huawei.com> > --- > drivers/staging/erofs/unzip_vle.c | 16 +++++----------- > 1 file changed, 5 insertions(+), 11 deletions(-) > > diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c > index 2b5951f233db..a127d8db76d8 100644 > --- a/drivers/staging/erofs/unzip_vle.c > +++ b/drivers/staging/erofs/unzip_vle.c > @@ -238,14 +238,9 @@ int erofs_try_to_free_cached_page(struct address_space *mapping, > { > struct erofs_sb_info *const sbi = EROFS_SB(mapping->host->i_sb); > const unsigned int clusterpages = erofs_clusterpages(sbi); > - > - struct z_erofs_vle_workgroup *grp; > + struct z_erofs_vle_workgroup *const grp = (void *)page_private(page); > int ret = 0; /* 0 - busy */ > > - /* prevent the workgroup from being freed */ > - rcu_read_lock(); > - grp = (void *)page_private(page); > - > if (erofs_workgroup_try_to_freeze(&grp->obj, 1)) { > unsigned int i; > > @@ -257,12 +252,11 @@ int erofs_try_to_free_cached_page(struct address_space *mapping, > } > } > erofs_workgroup_unfreeze(&grp->obj, 1); > - } > - rcu_read_unlock(); > > - if (ret) { > - ClearPagePrivate(page); > - put_page(page); > + if (ret) { > + ClearPagePrivate(page); > + put_page(page); > + } > } > return ret; > } > ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page 2019-02-20 2:38 ` Gao Xiang @ 2019-02-20 10:20 ` Greg Kroah-Hartman -1 siblings, 0 replies; 10+ messages in thread From: Greg Kroah-Hartman @ 2019-02-20 10:20 UTC (permalink / raw) On Wed, Feb 20, 2019@10:38:53AM +0800, Gao Xiang wrote: > Hi Greg, > > Could you consider take some time on these two patches for linux-5.1-rc1? > 1) staging: erofs: fix race of initializing xattrs of a inode at the same time > 2) staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page > > It will be of great help, especially patch 1 (it could cause potential memleak > in the race condition without it). Ok, I'll queue them up now, I was waiting for reviewed-by tags from others to show up :) greg k-h ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page @ 2019-02-20 10:20 ` Greg Kroah-Hartman 0 siblings, 0 replies; 10+ messages in thread From: Greg Kroah-Hartman @ 2019-02-20 10:20 UTC (permalink / raw) To: Gao Xiang Cc: devel, Chao Yu, linux-erofs, Chao Yu, LKML, weidu.du, Fang Wei, Miao Xie On Wed, Feb 20, 2019 at 10:38:53AM +0800, Gao Xiang wrote: > Hi Greg, > > Could you consider take some time on these two patches for linux-5.1-rc1? > 1) staging: erofs: fix race of initializing xattrs of a inode at the same time > 2) staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page > > It will be of great help, especially patch 1 (it could cause potential memleak > in the race condition without it). Ok, I'll queue them up now, I was waiting for reviewed-by tags from others to show up :) greg k-h ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page 2019-02-20 10:20 ` Greg Kroah-Hartman @ 2019-02-20 10:33 ` Gao Xiang -1 siblings, 0 replies; 10+ messages in thread From: Gao Xiang @ 2019-02-20 10:33 UTC (permalink / raw) On 2019/2/20 18:20, Greg Kroah-Hartman wrote: > On Wed, Feb 20, 2019@10:38:53AM +0800, Gao Xiang wrote: >> Hi Greg, >> >> Could you consider take some time on these two patches for linux-5.1-rc1? >> 1) staging: erofs: fix race of initializing xattrs of a inode at the same time >> 2) staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page >> >> It will be of great help, especially patch 1 (it could cause potential memleak >> in the race condition without it). > > Ok, I'll queue them up now, I was waiting for reviewed-by tags from > others to show up :) Thanks! :) Gao Xiang > > greg k-h > ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page @ 2019-02-20 10:33 ` Gao Xiang 0 siblings, 0 replies; 10+ messages in thread From: Gao Xiang @ 2019-02-20 10:33 UTC (permalink / raw) To: Greg Kroah-Hartman Cc: devel, Chao Yu, linux-erofs, Chao Yu, LKML, weidu.du, Fang Wei, Miao Xie On 2019/2/20 18:20, Greg Kroah-Hartman wrote: > On Wed, Feb 20, 2019 at 10:38:53AM +0800, Gao Xiang wrote: >> Hi Greg, >> >> Could you consider take some time on these two patches for linux-5.1-rc1? >> 1) staging: erofs: fix race of initializing xattrs of a inode at the same time >> 2) staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page >> >> It will be of great help, especially patch 1 (it could cause potential memleak >> in the race condition without it). > > Ok, I'll queue them up now, I was waiting for reviewed-by tags from > others to show up :) Thanks! :) Gao Xiang > > greg k-h > ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2019-02-20 10:34 UTC | newest] Thread overview: 10+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2019-02-16 8:46 [PATCH] staging: erofs: remove rcu_read_lock() in erofs_try_to_free_cached_page Gao Xiang 2019-02-16 8:46 ` Gao Xiang 2019-02-20 1:26 ` Chao Yu 2019-02-20 1:26 ` Chao Yu 2019-02-20 2:38 ` Gao Xiang 2019-02-20 2:38 ` Gao Xiang 2019-02-20 10:20 ` Greg Kroah-Hartman 2019-02-20 10:20 ` Greg Kroah-Hartman 2019-02-20 10:33 ` Gao Xiang 2019-02-20 10:33 ` Gao Xiang
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