diff options
author | Shyam Prasad N <sprasad@microsoft.com> | 2022-01-01 12:50:21 +0000 |
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committer | Steve French <stfrench@microsoft.com> | 2022-06-22 19:51:43 -0500 |
commit | aa45dadd34e44fcd6a9df4b395bee5b5633b4cec (patch) | |
tree | 102dd763484880c7a29ff85367b28be52ffcbf8f /fs/cifs/sess.c | |
parent | 9de74996a739bf0b7b5d8c260bd207ad6007442b (diff) | |
download | lwn-aa45dadd34e44fcd6a9df4b395bee5b5633b4cec.tar.gz lwn-aa45dadd34e44fcd6a9df4b395bee5b5633b4cec.zip |
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.c | 78 |
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); |