From: Shyam Prasad N <sprasad@microsoft.com>
Date: Sat, 1 Jan 2022 12:50:21 +0000
Subject: [PATCH] cifs: change iface_list from array to sorted linked list
Git-commit: aa45dadd34e44fcd6a9df4b395bee5b5633b4cec
References: bsc#1193629
Patch-mainline: v5.19-rc4
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>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
fs/cifs/cifs_debug.c | 12 +--
fs/cifs/cifsglob.h | 54 +++++++++++++-
fs/cifs/connect.c | 6 +-
fs/cifs/misc.c | 9 ++-
fs/cifs/sess.c | 78 ++++++++++----------
fs/cifs/smb2ops.c | 171 ++++++++++++++++++++++---------------------
6 files changed, 201 insertions(+), 129 deletions(-)
diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 1dd995efd5b8..2cfbac8bb965 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -162,6 +162,8 @@ cifs_dump_iface(struct seq_file *m, struct cifs_server_iface *iface)
seq_printf(m, "\t\tIPv4: %pI4\n", &ipv4->sin_addr);
else if (iface->sockaddr.ss_family == AF_INET6)
seq_printf(m, "\t\tIPv6: %pI6\n", &ipv6->sin6_addr);
+ if (!iface->is_active)
+ seq_puts(m, "\t\t[for-cleanup]\n");
}
static int cifs_debug_files_proc_show(struct seq_file *m, void *v)
@@ -221,6 +223,7 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
struct TCP_Server_Info *server;
struct cifs_ses *ses;
struct cifs_tcon *tcon;
+ struct cifs_server_iface *iface;
int c, i, j;
seq_puts(m,
@@ -456,11 +459,10 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
if (ses->iface_count)
seq_printf(m, "\n\n\tServer interfaces: %zu",
ses->iface_count);
- for (j = 0; j < ses->iface_count; j++) {
- struct cifs_server_iface *iface;
-
- iface = &ses->iface_list[j];
- seq_printf(m, "\n\t%d)", j+1);
+ j = 0;
+ list_for_each_entry(iface, &ses->iface_list,
+ iface_head) {
+ seq_printf(m, "\n\t%d)", ++j);
cifs_dump_iface(m, iface);
if (is_ses_using_iface(ses, iface))
seq_puts(m, "\t\t[CONNECTED]\n");
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index e7737166e5b8..7fc2addc95a3 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -933,15 +933,67 @@ static inline void cifs_set_net_ns(struct TCP_Server_Info *srv, struct net *net)
#endif
struct cifs_server_iface {
+ struct list_head iface_head;
+ struct kref refcount;
size_t speed;
unsigned int rdma_capable : 1;
unsigned int rss_capable : 1;
+ unsigned int is_active : 1; /* unset if non existent */
struct sockaddr_storage sockaddr;
};
+/* release iface when last ref is dropped */
+static inline void
+release_iface(struct kref *ref)
+{
+ struct cifs_server_iface *iface = container_of(ref,
+ struct cifs_server_iface,
+ refcount);
+ list_del_init(&iface->iface_head);
+ kfree(iface);
+}
+
+/*
+ * compare two interfaces a and b
+ * return 0 if everything matches.
+ * return 1 if a has higher link speed, or rdma capable, or rss capable
+ * return -1 otherwise.
+ */
+static inline int
+iface_cmp(struct cifs_server_iface *a, struct cifs_server_iface *b)
+{
+ int cmp_ret = 0;
+
+ WARN_ON(!a || !b);
+ if (a->speed == b->speed) {
+ if (a->rdma_capable == b->rdma_capable) {
+ if (a->rss_capable == b->rss_capable) {
+ cmp_ret = memcmp(&a->sockaddr, &b->sockaddr,
+ sizeof(a->sockaddr));
+ if (!cmp_ret)
+ return 0;
+ else if (cmp_ret > 0)
+ return 1;
+ else
+ return -1;
+ } else if (a->rss_capable > b->rss_capable)
+ return 1;
+ else
+ return -1;
+ } else if (a->rdma_capable > b->rdma_capable)
+ return 1;
+ else
+ return -1;
+ } else if (a->speed > b->speed)
+ return 1;
+ else
+ return -1;
+}
+
struct cifs_chan {
unsigned int in_reconnect : 1; /* if session setup in progress for this channel */
struct TCP_Server_Info *server;
+ struct cifs_server_iface *iface; /* interface in use */
__u8 signkey[SMB3_SIGN_KEY_SIZE];
};
@@ -993,7 +1045,7 @@ struct cifs_ses {
*/
spinlock_t iface_lock;
/* ========= begin: protected by iface_lock ======== */
- struct cifs_server_iface *iface_list;
+ struct list_head iface_list;
size_t iface_count;
unsigned long iface_last_update; /* jiffies */
/* ========= end: protected by iface_lock ======== */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 1849e3411487..248fe1805c17 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1894,9 +1894,11 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
int i;
for (i = 1; i < chan_count; i++) {
- spin_unlock(&ses->chan_lock);
+ if (ses->chans[i].iface) {
+ kref_put(&ses->chans[i].iface->refcount, release_iface);
+ ses->chans[i].iface = NULL;
+ }
cifs_put_tcp_session(ses->chans[i].server, 0);
- spin_lock(&ses->chan_lock);
ses->chans[i].server = NULL;
}
}
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index c69e1240d730..0e84e6fcf8ab 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -75,6 +75,7 @@ sesInfoAlloc(void)
INIT_LIST_HEAD(&ret_buf->tcon_list);
mutex_init(&ret_buf->session_mutex);
spin_lock_init(&ret_buf->iface_lock);
+ INIT_LIST_HEAD(&ret_buf->iface_list);
spin_lock_init(&ret_buf->chan_lock);
}
return ret_buf;
@@ -83,6 +84,8 @@ sesInfoAlloc(void)
void
sesInfoFree(struct cifs_ses *buf_to_free)
{
+ struct cifs_server_iface *iface = NULL, *niface = NULL;
+
if (buf_to_free == NULL) {
cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
return;
@@ -96,7 +99,11 @@ sesInfoFree(struct cifs_ses *buf_to_free)
kfree(buf_to_free->user_name);
kfree(buf_to_free->domainName);
kfree_sensitive(buf_to_free->auth_key.response);
- kfree(buf_to_free->iface_list);
+ spin_lock(&buf_to_free->iface_lock);
+ list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
+ iface_head)
+ kref_put(&iface->refcount, release_iface);
+ spin_unlock(&buf_to_free->iface_lock);
kfree_sensitive(buf_to_free);
}
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);
@@ -184,33 +182,17 @@ 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);
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 8543cafdfd34..db4ccf1d235e 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -512,73 +512,41 @@ smb3_negotiate_rsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx)
static int
parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
size_t buf_len,
- struct cifs_server_iface **iface_list,
- size_t *iface_count)
+ struct cifs_ses *ses)
{
struct network_interface_info_ioctl_rsp *p;
struct sockaddr_in *addr4;
struct sockaddr_in6 *addr6;
struct iface_info_ipv4 *p4;
struct iface_info_ipv6 *p6;
- struct cifs_server_iface *info;
+ struct cifs_server_iface *info = NULL, *iface = NULL, *niface = NULL;
+ struct cifs_server_iface tmp_iface;
ssize_t bytes_left;
size_t next = 0;
int nb_iface = 0;
- int rc = 0;
-
- *iface_list = NULL;
- *iface_count = 0;
-
- /*
- * Fist pass: count and sanity check
- */
+ int rc = 0, ret = 0;
bytes_left = buf_len;
p = buf;
- while (bytes_left >= sizeof(*p)) {
- nb_iface++;
- next = le32_to_cpu(p->Next);
- if (!next) {
- bytes_left -= sizeof(*p);
- break;
- }
- p = (struct network_interface_info_ioctl_rsp *)((u8 *)p+next);
- bytes_left -= next;
- }
-
- if (!nb_iface) {
- cifs_dbg(VFS, "%s: malformed interface info\n", __func__);
- rc = -EINVAL;
- goto out;
- }
-
- /* Azure rounds the buffer size up 8, to a 16 byte boundary */
- if ((bytes_left > 8) || p->Next)
- cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);
-
+ spin_lock(&ses->iface_lock);
/*
- * Second pass: extract info to internal structure
+ * Go through iface_list and do kref_put to remove
+ * any unused ifaces. ifaces in use will be removed
+ * when the last user calls a kref_put on it
*/
-
- *iface_list = kcalloc(nb_iface, sizeof(**iface_list), GFP_KERNEL);
- if (!*iface_list) {
- rc = -ENOMEM;
- goto out;
+ list_for_each_entry_safe(iface, niface, &ses->iface_list,
+ iface_head) {
+ iface->is_active = 0;
+ kref_put(&iface->refcount, release_iface);
}
+ spin_unlock(&ses->iface_lock);
- info = *iface_list;
- bytes_left = buf_len;
- p = buf;
while (bytes_left >= sizeof(*p)) {
- info->speed = le64_to_cpu(p->LinkSpeed);
- info->rdma_capable = le32_to_cpu(p->Capability & RDMA_CAPABLE) ? 1 : 0;
- info->rss_capable = le32_to_cpu(p->Capability & RSS_CAPABLE) ? 1 : 0;
-
- cifs_dbg(FYI, "%s: adding iface %zu\n", __func__, *iface_count);
- cifs_dbg(FYI, "%s: speed %zu bps\n", __func__, info->speed);
- cifs_dbg(FYI, "%s: capabilities 0x%08x\n", __func__,
- le32_to_cpu(p->Capability));
+ memset(&tmp_iface, 0, sizeof(tmp_iface));
+ tmp_iface.speed = le64_to_cpu(p->LinkSpeed);
+ tmp_iface.rdma_capable = le32_to_cpu(p->Capability & RDMA_CAPABLE) ? 1 : 0;
+ tmp_iface.rss_capable = le32_to_cpu(p->Capability & RSS_CAPABLE) ? 1 : 0;
switch (p->Family) {
/*
@@ -587,7 +555,7 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
* conversion explicit in case either one changes.
*/
case INTERNETWORK:
- addr4 = (struct sockaddr_in *)&info->sockaddr;
+ addr4 = (struct sockaddr_in *)&tmp_iface.sockaddr;
p4 = (struct iface_info_ipv4 *)p->Buffer;
addr4->sin_family = AF_INET;
memcpy(&addr4->sin_addr, &p4->IPv4Address, 4);
@@ -599,7 +567,7 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
&addr4->sin_addr);
break;
case INTERNETWORKV6:
- addr6 = (struct sockaddr_in6 *)&info->sockaddr;
+ addr6 = (struct sockaddr_in6 *)&tmp_iface.sockaddr;
p6 = (struct iface_info_ipv6 *)p->Buffer;
addr6->sin6_family = AF_INET6;
memcpy(&addr6->sin6_addr, &p6->IPv6Address, 16);
@@ -619,46 +587,96 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
goto next_iface;
}
- (*iface_count)++;
- info++;
+ /*
+ * The iface_list is assumed to be sorted by speed.
+ * Check if the new interface exists in that list.
+ * NEVER change iface. it could be in use.
+ * Add a new one instead
+ */
+ spin_lock(&ses->iface_lock);
+ iface = niface = NULL;
+ list_for_each_entry_safe(iface, niface, &ses->iface_list,
+ iface_head) {
+ ret = iface_cmp(iface, &tmp_iface);
+ if (!ret) {
+ /* just get a ref so that it doesn't get picked/freed */
+ iface->is_active = 1;
+ kref_get(&iface->refcount);
+ spin_unlock(&ses->iface_lock);
+ goto next_iface;
+ } else if (ret < 0) {
+ /* all remaining ifaces are slower */
+ kref_get(&iface->refcount);
+ break;
+ }
+ }
+ spin_unlock(&ses->iface_lock);
+
+ /* no match. insert the entry in the list */
+ info = kmalloc(sizeof(struct cifs_server_iface),
+ GFP_KERNEL);
+ if (!info) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ memcpy(info, &tmp_iface, sizeof(tmp_iface));
+
+ /* add this new entry to the list */
+ kref_init(&info->refcount);
+ info->is_active = 1;
+
+ cifs_dbg(FYI, "%s: adding iface %zu\n", __func__, ses->iface_count);
+ cifs_dbg(FYI, "%s: speed %zu bps\n", __func__, info->speed);
+ cifs_dbg(FYI, "%s: capabilities 0x%08x\n", __func__,
+ le32_to_cpu(p->Capability));
+
+ spin_lock(&ses->iface_lock);
+ if (!list_entry_is_head(iface, &ses->iface_list, iface_head)) {
+ list_add_tail(&info->iface_head, &iface->iface_head);
+ kref_put(&iface->refcount, release_iface);
+ } else
+ list_add_tail(&info->iface_head, &ses->iface_list);
+ spin_unlock(&ses->iface_lock);
+
+ ses->iface_count++;
+ ses->iface_last_update = jiffies;
next_iface:
+ nb_iface++;
next = le32_to_cpu(p->Next);
- if (!next)
+ if (!next) {
+ bytes_left -= sizeof(*p);
break;
+ }
p = (struct network_interface_info_ioctl_rsp *)((u8 *)p+next);
bytes_left -= next;
}
- if (!*iface_count) {
+ if (!nb_iface) {
+ cifs_dbg(VFS, "%s: malformed interface info\n", __func__);
+ rc = -EINVAL;
+ goto out;
+ }
+
+ /* Azure rounds the buffer size up 8, to a 16 byte boundary */
+ if ((bytes_left > 8) || p->Next)
+ cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);
+
+
+ if (!ses->iface_count) {
rc = -EINVAL;
goto out;
}
out:
- if (rc) {
- kfree(*iface_list);
- *iface_count = 0;
- *iface_list = NULL;
- }
return rc;
}
-static int compare_iface(const void *ia, const void *ib)
-{
- const struct cifs_server_iface *a = (struct cifs_server_iface *)ia;
- const struct cifs_server_iface *b = (struct cifs_server_iface *)ib;
-
- return a->speed == b->speed ? 0 : (a->speed > b->speed ? -1 : 1);
-}
-
static int
SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon)
{
int rc;
unsigned int ret_data_len = 0;
struct network_interface_info_ioctl_rsp *out_buf = NULL;
- struct cifs_server_iface *iface_list;
- size_t iface_count;
struct cifs_ses *ses = tcon->ses;
rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
@@ -674,21 +692,10 @@ SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon)
goto out;
}
- rc = parse_server_interfaces(out_buf, ret_data_len,
- &iface_list, &iface_count);
+ rc = parse_server_interfaces(out_buf, ret_data_len, ses);
if (rc)
goto out;
- /* sort interfaces from fastest to slowest */
- sort(iface_list, iface_count, sizeof(*iface_list), compare_iface, NULL);
-
- spin_lock(&ses->iface_lock);
- kfree(ses->iface_list);
- ses->iface_list = iface_list;
- ses->iface_count = iface_count;
- ses->iface_last_update = jiffies;
- spin_unlock(&ses->iface_lock);
-
out:
kfree(out_buf);
return rc;
--
2.37.3