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authorBenoît Ganne <bganne@cisco.com>2021-04-29 18:24:24 +0200
committerDamjan Marion <dmarion@me.com>2021-05-21 19:50:14 +0000
commita42c41be4eed3e1ce2a42038b07ce1d3420891cd (patch)
treefc95c7c24cbef993cc2bef8742b3360123d70b66 /src/plugins/af_xdp/af_xdp.h
parent92a8d761c412590f5112239be4c511091b2b2d5a (diff)
af_xdp: workaround kernel race between poll() and sendmsg()
Prior to Linux 5.6 there is a race condition between poll() and sendmsg() in the kernel. This patch protects the syscalls with a lock to prevent it, unless the NO_SYSCALL_LOCK flag is set at create time. See https://lore.kernel.org/bpf/BYAPR11MB365382C5DB1E5FCC53242609C1549@BYAPR11MB3653.namprd11.prod.outlook.com/ Type: fix Change-Id: Ie7d4f5cb41f697b11a09b6046e54d190430d76df Signed-off-by: Benoît Ganne <bganne@cisco.com>
Diffstat (limited to 'src/plugins/af_xdp/af_xdp.h')
-rw-r--r--src/plugins/af_xdp/af_xdp.h30
1 files changed, 24 insertions, 6 deletions
diff --git a/src/plugins/af_xdp/af_xdp.h b/src/plugins/af_xdp/af_xdp.h
index 568380baa56..91895ced23b 100644
--- a/src/plugins/af_xdp/af_xdp.h
+++ b/src/plugins/af_xdp/af_xdp.h
@@ -32,7 +32,8 @@
_ (1, ERROR, "error") \
_ (2, ADMIN_UP, "admin-up") \
_ (3, LINK_UP, "link-up") \
- _ (4, ZEROCOPY, "zero-copy")
+ _ (4, ZEROCOPY, "zero-copy") \
+ _ (5, SYSCALL_LOCK, "syscall-lock")
enum
{
@@ -49,12 +50,20 @@ enum
clib_error_free(err_); \
}
+typedef enum
+{
+ AF_XDP_RXQ_MODE_UNKNOWN,
+ AF_XDP_RXQ_MODE_POLLING,
+ AF_XDP_RXQ_MODE_INTERRUPT,
+} __clib_packed af_xdp_rxq_mode_t;
+
typedef struct
{
CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
/* fields below are accessed in data-plane (hot) */
+ clib_spinlock_t syscall_lock;
struct xsk_ring_cons rx;
struct xsk_ring_prod fq;
int xsk_fd;
@@ -63,7 +72,7 @@ typedef struct
uword file_index;
u32 queue_index;
- u8 is_polling;
+ af_xdp_rxq_mode_t mode;
} af_xdp_rxq_t;
typedef struct
@@ -73,6 +82,7 @@ typedef struct
/* fields below are accessed in data-plane (hot) */
clib_spinlock_t lock;
+ clib_spinlock_t syscall_lock;
struct xsk_ring_prod tx;
struct xsk_ring_cons cq;
int xsk_fd;
@@ -101,6 +111,8 @@ typedef struct
u32 dev_instance;
u8 hwaddr[6];
+ u8 rxq_num;
+
struct xsk_umem **umem;
struct xsk_socket **xsk;
@@ -127,12 +139,18 @@ typedef enum
AF_XDP_MODE_ZERO_COPY = 2,
} af_xdp_mode_t;
+typedef enum
+{
+ AF_XDP_CREATE_FLAGS_NO_SYSCALL_LOCK = 1,
+} af_xdp_create_flag_t;
+
typedef struct
{
char *linux_ifname;
char *name;
char *prog;
af_xdp_mode_t mode;
+ af_xdp_create_flag_t flags;
u32 rxq_size;
u32 txq_size;
u32 rxq_num;
@@ -163,10 +181,10 @@ typedef struct
u32 hw_if_index;
} af_xdp_input_trace_t;
-#define foreach_af_xdp_tx_func_error \
-_(NO_FREE_SLOTS, "no free tx slots") \
-_(SENDTO_REQUIRED, "sendto required") \
-_(SENDTO_FAILURES, "sendto failures")
+#define foreach_af_xdp_tx_func_error \
+ _ (NO_FREE_SLOTS, "no free tx slots") \
+ _ (SYSCALL_REQUIRED, "syscall required") \
+ _ (SYSCALL_FAILURES, "syscall failures")
typedef enum
{