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authorShyam Prasad N <sprasad@microsoft.com>2022-01-01 15:50:21 +0300
committerSteve French <stfrench@microsoft.com>2022-06-23 03:51:43 +0300
commitaa45dadd34e44fcd6a9df4b395bee5b5633b4cec (patch)
tree102dd763484880c7a29ff85367b28be52ffcbf8f /fs/cifs/sess.c
parent9de74996a739bf0b7b5d8c260bd207ad6007442b (diff)
downloadlinux-aa45dadd34e44fcd6a9df4b395bee5b5633b4cec.tar.xz
cifs: change iface_list from array to sorted linked list
A server's published interface list can change over time, and needs to be updated. We've storing iface_list as a simple array, which makes it difficult to manipulate an existing list. With this change, iface_list is modified into a linked list of interfaces, which is kept sorted by speed. Also added a reference counter for an iface entry, so that each channel can maintain a backpointer to the iface and drop it easily when needed. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs/sess.c')
-rw-r--r--fs/cifs/sess.c78
1 files changed, 40 insertions, 38 deletions
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index d417de354d9d..d7b6e5687df2 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -58,7 +58,7 @@ bool is_ses_using_iface(struct cifs_ses *ses, struct cifs_server_iface *iface)
spin_lock(&ses->chan_lock);
for (i = 0; i < ses->chan_count; i++) {
- if (is_server_using_iface(ses->chans[i].server, iface)) {
+ if (ses->chans[i].iface == iface) {
spin_unlock(&ses->chan_lock);
return true;
}
@@ -151,11 +151,9 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
{
int old_chan_count, new_chan_count;
int left;
- int i = 0;
int rc = 0;
int tries = 0;
- struct cifs_server_iface *ifaces = NULL;
- size_t iface_count;
+ struct cifs_server_iface *iface = NULL, *niface = NULL;
spin_lock(&ses->chan_lock);
@@ -185,32 +183,16 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
spin_unlock(&ses->chan_lock);
/*
- * Make a copy of the iface list at the time and use that
- * instead so as to not hold the iface spinlock for opening
- * channels
- */
- spin_lock(&ses->iface_lock);
- iface_count = ses->iface_count;
- if (iface_count <= 0) {
- spin_unlock(&ses->iface_lock);
- cifs_dbg(VFS, "no iface list available to open channels\n");
- return 0;
- }
- ifaces = kmemdup(ses->iface_list, iface_count*sizeof(*ifaces),
- GFP_ATOMIC);
- if (!ifaces) {
- spin_unlock(&ses->iface_lock);
- return 0;
- }
- spin_unlock(&ses->iface_lock);
-
- /*
* Keep connecting to same, fastest, iface for all channels as
* long as its RSS. Try next fastest one if not RSS or channel
* creation fails.
*/
+ spin_lock(&ses->iface_lock);
+ iface = list_first_entry(&ses->iface_list, struct cifs_server_iface,
+ iface_head);
+ spin_unlock(&ses->iface_lock);
+
while (left > 0) {
- struct cifs_server_iface *iface;
tries++;
if (tries > 3*ses->chan_max) {
@@ -219,27 +201,46 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
break;
}
- iface = &ifaces[i];
- if (is_ses_using_iface(ses, iface) && !iface->rss_capable) {
- i = (i+1) % iface_count;
- continue;
+ spin_lock(&ses->iface_lock);
+ if (!ses->iface_count) {
+ spin_unlock(&ses->iface_lock);
+ break;
}
- rc = cifs_ses_add_channel(cifs_sb, ses, iface);
- if (rc) {
- cifs_dbg(FYI, "failed to open extra channel on iface#%d rc=%d\n",
- i, rc);
- i = (i+1) % iface_count;
- continue;
+ list_for_each_entry_safe_from(iface, niface, &ses->iface_list,
+ iface_head) {
+ /* skip ifaces that are unusable */
+ if (!iface->is_active ||
+ (is_ses_using_iface(ses, iface) &&
+ !iface->rss_capable)) {
+ continue;
+ }
+
+ /* take ref before unlock */
+ kref_get(&iface->refcount);
+
+ spin_unlock(&ses->iface_lock);
+ rc = cifs_ses_add_channel(cifs_sb, ses, iface);
+ spin_lock(&ses->iface_lock);
+
+ if (rc) {
+ cifs_dbg(VFS, "failed to open extra channel on iface:%pIS rc=%d\n",
+ &iface->sockaddr,
+ rc);
+ kref_put(&iface->refcount, release_iface);
+ continue;
+ }
+
+ cifs_dbg(FYI, "successfully opened new channel on iface:%pIS\n",
+ &iface->sockaddr);
+ break;
}
+ spin_unlock(&ses->iface_lock);
- cifs_dbg(FYI, "successfully opened new channel on iface#%d\n",
- i);
left--;
new_chan_count++;
}
- kfree(ifaces);
return new_chan_count - old_chan_count;
}
@@ -355,6 +356,7 @@ cifs_ses_add_channel(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
spin_unlock(&ses->chan_lock);
goto out;
}
+ chan->iface = iface;
ses->chan_count++;
atomic_set(&ses->chan_seq, 0);