X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=ipc%2Fmsg.c;h=245db1140ad66a2be47744f02ef0d80deea5006f;hb=ffa571dafbaec0c74e374ce0ea7b4212b6cbc94c;hp=558aa91186b6ced1a27b1e05b65c5ee129e0a175;hpb=b746f9c7941f227ad582b4f0bc981f3adcbc46b2;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

diff --git a/ipc/msg.c b/ipc/msg.c
index 558aa91..245db11 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -253,8 +253,14 @@ static void expunge_all(struct msg_queue *msq, int res)
 	struct msg_receiver *msr, *t;
 
 	list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
-		msr->r_msg = NULL;
+		msr->r_msg = NULL; /* initialize expunge ordering */
 		wake_up_process(msr->r_tsk);
+		/*
+		 * Ensure that the wakeup is visible before setting r_msg as
+		 * the receiving end depends on it: either spinning on a nil,
+		 * or dealing with -EAGAIN cases. See lockless receive part 1
+		 * and 2 in do_msgrcv().
+		 */
 		smp_mb();
 		msr->r_msg = ERR_PTR(res);
 	}
@@ -318,7 +324,7 @@ SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
 static inline unsigned long
 copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
 {
-	switch(version) {
+	switch (version) {
 	case IPC_64:
 		return copy_to_user(buf, in, sizeof(*in));
 	case IPC_OLD:
@@ -363,7 +369,7 @@ copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
 static inline unsigned long
 copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
 {
-	switch(version) {
+	switch (version) {
 	case IPC_64:
 		if (copy_from_user(out, buf, sizeof(*out)))
 			return -EFAULT;
@@ -375,9 +381,9 @@ copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
 		if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 			return -EFAULT;
 
-		out->msg_perm.uid      	= tbuf_old.msg_perm.uid;
-		out->msg_perm.gid      	= tbuf_old.msg_perm.gid;
-		out->msg_perm.mode     	= tbuf_old.msg_perm.mode;
+		out->msg_perm.uid	= tbuf_old.msg_perm.uid;
+		out->msg_perm.gid	= tbuf_old.msg_perm.gid;
+		out->msg_perm.mode	= tbuf_old.msg_perm.mode;
 
 		if (tbuf_old.msg_qbytes == 0)
 			out->msg_qbytes	= tbuf_old.msg_lqbytes;
@@ -606,13 +612,13 @@ SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
 
 static int testmsg(struct msg_msg *msg, long type, int mode)
 {
-	switch(mode)
+	switch (mode)
 	{
 		case SEARCH_ANY:
 		case SEARCH_NUMBER:
 			return 1;
 		case SEARCH_LESSEQUAL:
-			if (msg->m_type <=type)
+			if (msg->m_type <= type)
 				return 1;
 			break;
 		case SEARCH_EQUAL:
@@ -638,15 +644,22 @@ static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
 
 			list_del(&msr->r_list);
 			if (msr->r_maxsize < msg->m_ts) {
+				/* initialize pipelined send ordering */
 				msr->r_msg = NULL;
 				wake_up_process(msr->r_tsk);
-				smp_mb();
+				smp_mb(); /* see barrier comment below */
 				msr->r_msg = ERR_PTR(-E2BIG);
 			} else {
 				msr->r_msg = NULL;
 				msq->q_lrpid = task_pid_vnr(msr->r_tsk);
 				msq->q_rtime = get_seconds();
 				wake_up_process(msr->r_tsk);
+				/*
+				 * Ensure that the wakeup is visible before
+				 * setting r_msg, as the receiving end depends
+				 * on it. See lockless receive part 1 and 2 in
+				 * do_msgrcv().
+				 */
 				smp_mb();
 				msr->r_msg = msg;
 
@@ -654,6 +667,7 @@ static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
 			}
 		}
 	}
+
 	return 0;
 }
 
@@ -696,7 +710,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
 			goto out_unlock0;
 
 		/* raced with RMID? */
-		if (msq->q_perm.deleted) {
+		if (!ipc_valid_object(&msq->q_perm)) {
 			err = -EIDRM;
 			goto out_unlock0;
 		}
@@ -716,6 +730,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
 			goto out_unlock0;
 		}
 
+		/* enqueue the sender and prepare to block */
 		ss_add(msq, &s);
 
 		if (!ipc_rcu_getref(msq)) {
@@ -731,7 +746,8 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
 		ipc_lock_object(&msq->q_perm);
 
 		ipc_rcu_putref(msq, ipc_rcu_free);
-		if (msq->q_perm.deleted) {
+		/* raced with RMID? */
+		if (!ipc_valid_object(&msq->q_perm)) {
 			err = -EIDRM;
 			goto out_unlock0;
 		}
@@ -909,7 +925,7 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgfl
 		ipc_lock_object(&msq->q_perm);
 
 		/* raced with RMID? */
-		if (msq->q_perm.deleted) {
+		if (!ipc_valid_object(&msq->q_perm)) {
 			msg = ERR_PTR(-EIDRM);
 			goto out_unlock0;
 		}
@@ -983,7 +999,7 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgfl
 		 * wake_up_process(). There is a race with exit(), see
 		 * ipc/mqueue.c for the details.
 		 */
-		msg = (struct msg_msg*)msr_d.r_msg;
+		msg = (struct msg_msg *)msr_d.r_msg;
 		while (msg == NULL) {
 			cpu_relax();
 			msg = (struct msg_msg *)msr_d.r_msg;
@@ -1004,7 +1020,7 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgfl
 		/* Lockless receive, part 4:
 		 * Repeat test after acquiring the spinlock.
 		 */
-		msg = (struct msg_msg*)msr_d.r_msg;
+		msg = (struct msg_msg *)msr_d.r_msg;
 		if (msg != ERR_PTR(-EAGAIN))
 			goto out_unlock0;