Messages in this thread | | | From | NeilBrown <> | Date | Sat, 11 Apr 2020 14:10:30 +1000 | Subject | Re: ping: [PATCH v3] NFS:remove redundant call to nfs_do_access |
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On Sat, Apr 11 2020, Zhouyi Zhou wrote:
> ping
You patch has landed in Linux.
Commit eb095c14030f ("NFS:remove redundant call to nfs_do_access")
Thanks, NeilBrown
> > On 3/6/20, Zhouyi Zhou <zhouzhouyi@gmail.com> wrote: >> In function nfs_permission: >> 1. the rcu_read_lock and rcu_read_unlock around nfs_do_access >> is unnecessary because the rcu critical data structure is already >> protected in subsidiary function nfs_access_get_cached_rcu. No other >> data structure needs rcu_read_lock in nfs_do_access. >> >> 2. call nfs_do_access once is enough, because: >> 2-1. when mask has MAY_NOT_BLOCK bit >> The second call to nfs_do_access will not happen. >> >> 2-2. when mask has no MAY_NOT_BLOCK bit >> The second call to nfs_do_access will happen if res == -ECHILD, which >> means the first nfs_do_access goes out after statement if (!may_block). >> The second call to nfs_do_access will go through this procedure once >> again except continue the work after if (!may_block). >> But above work can be performed by only one call to nfs_do_access >> without mangling the mask flag. >> >> Tested in x86_64 >> Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> >> --- >> fs/nfs/dir.c | 9 +-------- >> 1 files changed, 1 insertions(+), 8 deletions(-) >> >> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c >> index 193d6fb..37b0c10 100644 >> --- a/fs/nfs/dir.c >> +++ b/fs/nfs/dir.c >> @@ -2732,14 +2732,7 @@ int nfs_permission(struct inode *inode, int mask) >> if (!NFS_PROTO(inode)->access) >> goto out_notsup; >> >> - /* Always try fast lookups first */ >> - rcu_read_lock(); >> - res = nfs_do_access(inode, cred, mask|MAY_NOT_BLOCK); >> - rcu_read_unlock(); >> - if (res == -ECHILD && !(mask & MAY_NOT_BLOCK)) { >> - /* Fast lookup failed, try the slow way */ >> - res = nfs_do_access(inode, cred, mask); >> - } >> + res = nfs_do_access(inode, cred, mask); >> out: >> if (!res && (mask & MAY_EXEC)) >> res = nfs_execute_ok(inode, mask); >> -- >> 1.7.1 >> >> [unhandled content-type:application/pgp-signature] | |