| Message ID | 153628137216.8267.15666994772553520296.stgit@noble (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Beginning of multi-rail support for drivers/staging/lustre | expand |
It seems the selection code being affected by this patch later gets moved to its own routine called lnet_select_pathway(). The logic is completely re-written so it may not be important to fix the use of locks here. However, it is not good that the lock is not being held while checking for shutdown. Reviewed-by: Doug Oucharek <dougso@me.com> Doug On 9/6/18, 5:54 PM, "NeilBrown" <neilb@suse.com> wrote: ln_shutdown returns -ESHUTDOWN if ln_shutdown is already set. The lock is always taken to set ln_shutdown, but apparently we don't need to hold the lock for this test. I guess if it is set immediately after the test, and before we take the lock then.... can anything bad happen? This is part of 8cbb8cd3e771e7f7e0f99cafc19fad32770dc015 LU-7734 lnet: Multi-Rail local NI split Signed-off-by: NeilBrown <neilb@suse.com> --- drivers/staging/lustre/lnet/lnet/lib-move.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/staging/lustre/lnet/lnet/lib-move.c b/drivers/staging/lustre/lnet/lnet/lib-move.c index 60f34c4b85d3..46e593fbb44f 100644 --- a/drivers/staging/lustre/lnet/lnet/lib-move.c +++ b/drivers/staging/lustre/lnet/lnet/lib-move.c @@ -1099,12 +1099,9 @@ lnet_send(lnet_nid_t src_nid, struct lnet_msg *msg, lnet_nid_t rtr_nid) cpt = lnet_cpt_of_nid(rtr_nid == LNET_NID_ANY ? dst_nid : rtr_nid, local_ni); again: - lnet_net_lock(cpt); - - if (the_lnet.ln_shutdown) { - lnet_net_unlock(cpt); + if (the_lnet.ln_shutdown) return -ESHUTDOWN; - } + lnet_net_lock(cpt); if (src_nid == LNET_NID_ANY) { src_ni = NULL;
On Wed, Sep 12 2018, Doug Oucharek wrote: > It seems the selection code being affected by this patch later gets moved to its own routine called lnet_select_pathway(). The logic is completely re-written so it may not be important to fix the use of locks here. However, it is not good that the lock is not being held while checking for shutdown. Thanks... I might drop the patch here, and probably fold it into which ever subsequent patch changes this code can gets rid of lnet_send(). I'll try that anyway. NeilBrown > > Reviewed-by: Doug Oucharek <dougso@me.com> > > Doug > > On 9/6/18, 5:54 PM, "NeilBrown" <neilb@suse.com> wrote: > > ln_shutdown returns -ESHUTDOWN if ln_shutdown > is already set. > The lock is always taken to set ln_shutdown, but apparently > we don't need to hold the lock for this test. > I guess if it is set immediately after the test, and before > we take the lock then.... can anything bad happen? > > This is part of > 8cbb8cd3e771e7f7e0f99cafc19fad32770dc015 > LU-7734 lnet: Multi-Rail local NI split > > Signed-off-by: NeilBrown <neilb@suse.com> > --- > drivers/staging/lustre/lnet/lnet/lib-move.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/drivers/staging/lustre/lnet/lnet/lib-move.c b/drivers/staging/lustre/lnet/lnet/lib-move.c > index 60f34c4b85d3..46e593fbb44f 100644 > --- a/drivers/staging/lustre/lnet/lnet/lib-move.c > +++ b/drivers/staging/lustre/lnet/lnet/lib-move.c > @@ -1099,12 +1099,9 @@ lnet_send(lnet_nid_t src_nid, struct lnet_msg *msg, lnet_nid_t rtr_nid) > cpt = lnet_cpt_of_nid(rtr_nid == LNET_NID_ANY ? dst_nid : rtr_nid, > local_ni); > again: > - lnet_net_lock(cpt); > - > - if (the_lnet.ln_shutdown) { > - lnet_net_unlock(cpt); > + if (the_lnet.ln_shutdown) > return -ESHUTDOWN; > - } > + lnet_net_lock(cpt); > > if (src_nid == LNET_NID_ANY) { > src_ni = NULL; > > >
diff --git a/drivers/staging/lustre/lnet/lnet/lib-move.c b/drivers/staging/lustre/lnet/lnet/lib-move.c index 60f34c4b85d3..46e593fbb44f 100644 --- a/drivers/staging/lustre/lnet/lnet/lib-move.c +++ b/drivers/staging/lustre/lnet/lnet/lib-move.c @@ -1099,12 +1099,9 @@ lnet_send(lnet_nid_t src_nid, struct lnet_msg *msg, lnet_nid_t rtr_nid) cpt = lnet_cpt_of_nid(rtr_nid == LNET_NID_ANY ? dst_nid : rtr_nid, local_ni); again: - lnet_net_lock(cpt); - - if (the_lnet.ln_shutdown) { - lnet_net_unlock(cpt); + if (the_lnet.ln_shutdown) return -ESHUTDOWN; - } + lnet_net_lock(cpt); if (src_nid == LNET_NID_ANY) { src_ni = NULL;
ln_shutdown returns -ESHUTDOWN if ln_shutdown is already set. The lock is always taken to set ln_shutdown, but apparently we don't need to hold the lock for this test. I guess if it is set immediately after the test, and before we take the lock then.... can anything bad happen? This is part of 8cbb8cd3e771e7f7e0f99cafc19fad32770dc015 LU-7734 lnet: Multi-Rail local NI split Signed-off-by: NeilBrown <neilb@suse.com> --- drivers/staging/lustre/lnet/lnet/lib-move.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)