[PATCH -next] cifs: Use GFP_ATOMIC when a lock is held in cifs_mount()

Tom Talpey ttalpey at microsoft.com
Tue Dec 18 15:21:44 UTC 2018


> -----Original Message-----
> From: linux-cifs-owner at vger.kernel.org <linux-cifs-owner at vger.kernel.org> On
> Behalf Of Steve French
> Sent: Monday, December 17, 2018 9:06 PM
> To: Paulo Alcantara <paulo at paulo.ac>
> Cc: YueHaibing <yuehaibing at huawei.com>; Steve French
> <sfrench at samba.org>; CIFS <linux-cifs at vger.kernel.org>; samba-technical
> <samba-technical at lists.samba.org>; kernel-janitors <kernel-
> janitors at vger.kernel.org>
> Subject: Re: [PATCH -next] cifs: Use GFP_ATOMIC when a lock is held in
> cifs_mount()
> 
> merged into cifs-2.6.git for-next
> 
> On Mon, Dec 17, 2018 at 7:58 PM Paulo Alcantara <paulo at paulo.ac> wrote:
> >
> >
> >
> > On December 17, 2018 11:34:39 PM GMT-02:00, YueHaibing
> <yuehaibing at huawei.com> wrote:
> > >A spin lock is held before kstrndup, it may sleep with holding
> > >the spinlock, so we should use GFP_ATOMIC instead.

Wouldn't it be better to allocate the memory before entering the
spinlock-protected section altogether?

Tom.

> > >Fixes: e58c31d5e387 ("cifs: Add support for failover in
> > >cifs_reconnect()")
> > >Signed-off-by: YueHaibing <yuehaibing at huawei.com>
> > >---
> > > fs/cifs/connect.c | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > >diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> > >index a83aa61..3d5e308 100644
> > >--- a/fs/cifs/connect.c
> > >+++ b/fs/cifs/connect.c
> > >@@ -4574,7 +4574,8 @@ int cifs_mount(struct cifs_sb_info *cifs_sb,
> > >struct smb_vol *vol)
> > >               tcon->remap = cifs_remap(cifs_sb);
> > >       }
> > >       cifs_sb->origin_fullpath = kstrndup(tcon->dfs_path,
> > >-                                          strlen(tcon->dfs_path), GFP_KERNEL);
> > >+                                          strlen(tcon->dfs_path),
> > >+                                          GFP_ATOMIC);
> > >       if (!cifs_sb->origin_fullpath) {
> > >               spin_unlock(&cifs_tcp_ses_lock);
> > >               rc = -ENOMEM;
> >
> > Reviewed-by: Paulo Alcantara <palcantara at suse.de>
> >
> > Thanks
> > Paulo
> > --
> > Sent from my Android device with K-9 Mail. Please excuse my brevity.
> 
> 
> 
> --
> Thanks,
> 
> Steve


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