blktrace: use BLKTRACE_BDEV_SIZE as the name size for setup structure

[linux-2.6.git] / block / blktrace.c

diff --git a/block/blktrace.c b/block/blktrace.c
index b2cbb4e5d7673c7a49ea557d962022f7ba3594f9..85049a7e7a179a97c283eb4ebe6c1fe7285f80cf 100644 (file)
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -75,6 +75,24 @@ static void trace_note_time(struct blk_trace *bt)
        local_irq_restore(flags);
 }
 
+void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
+{
+       int n;
+       va_list args;
+       unsigned long flags;
+       char *buf;
+
+       local_irq_save(flags);
+       buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
+       va_start(args, fmt);
+       n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
+       va_end(args);
+
+       trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
+       local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(__trace_note_message);
+
 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
                         pid_t pid)
 {
@@ -93,23 +111,9 @@ static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
  */
 static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) };
 
-/*
- * Bio action bits of interest
- */
-static u32 bio_act[9] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC), 0, BLK_TC_ACT(BLK_TC_AHEAD), 0, 0, 0, BLK_TC_ACT(BLK_TC_META) };
-
-/*
- * More could be added as needed, taking care to increment the decrementer
- * to get correct indexing
- */
-#define trace_barrier_bit(rw)  \
-       (((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0))
-#define trace_sync_bit(rw)     \
-       (((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1))
-#define trace_ahead_bit(rw)    \
-       (((rw) & (1 << BIO_RW_AHEAD)) << (2 - BIO_RW_AHEAD))
-#define trace_meta_bit(rw)     \
-       (((rw) & (1 << BIO_RW_META)) >> (BIO_RW_META - 3))
+/* The ilog2() calls fall out because they're constant */
+#define MASK_TC_BIT(rw, __name) ( (rw & (1 << BIO_RW_ ## __name)) << \
+         (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name) )
 
 /*
  * The worker for the various blk_add_trace*() types. Fills out a
@@ -129,10 +133,11 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
                return;
 
        what |= ddir_act[rw & WRITE];
-       what |= bio_act[trace_barrier_bit(rw)];
-       what |= bio_act[trace_sync_bit(rw)];
-       what |= bio_act[trace_ahead_bit(rw)];
-       what |= bio_act[trace_meta_bit(rw)];
+       what |= MASK_TC_BIT(rw, BARRIER);
+       what |= MASK_TC_BIT(rw, SYNC);
+       what |= MASK_TC_BIT(rw, AHEAD);
+       what |= MASK_TC_BIT(rw, META);
+       what |= MASK_TC_BIT(rw, DISCARD);
 
        pid = tsk->pid;
        if (unlikely(act_log_check(bt, what, sector, pid)))
@@ -141,10 +146,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
        /*
         * A word about the locking here - we disable interrupts to reserve
         * some space in the relay per-cpu buffer, to prevent an irq
-        * from coming in and stepping on our toes. Once reserved, it's
-        * enough to get preemption disabled to prevent read of this data
-        * before we are through filling it. get_cpu()/put_cpu() does this
-        * for us
+        * from coming in and stepping on our toes.
         */
        local_irq_save(flags);
 
@@ -229,9 +231,11 @@ err:
 static void blk_trace_cleanup(struct blk_trace *bt)
 {
        relay_close(bt->rchan);
+       debugfs_remove(bt->msg_file);
        debugfs_remove(bt->dropped_file);
        blk_remove_tree(bt->dir);
        free_percpu(bt->sequence);
+       free_percpu(bt->msg_data);
        kfree(bt);
 }
 
@@ -275,6 +279,44 @@ static const struct file_operations blk_dropped_fops = {
        .read =         blk_dropped_read,
 };
 
+static int blk_msg_open(struct inode *inode, struct file *filp)
+{
+       filp->private_data = inode->i_private;
+
+       return 0;
+}
+
+static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
+                               size_t count, loff_t *ppos)
+{
+       char *msg;
+       struct blk_trace *bt;
+
+       if (count > BLK_TN_MAX_MSG)
+               return -EINVAL;
+
+       msg = kmalloc(count, GFP_KERNEL);
+       if (msg == NULL)
+               return -ENOMEM;
+
+       if (copy_from_user(msg, buffer, count)) {
+               kfree(msg);
+               return -EFAULT;
+       }
+
+       bt = filp->private_data;
+       __trace_note_message(bt, "%s", msg);
+       kfree(msg);
+
+       return count;
+}
+
+static const struct file_operations blk_msg_fops = {
+       .owner =        THIS_MODULE,
+       .open =         blk_msg_open,
+       .write =        blk_msg_write,
+};
+
 /*
  * Keep track of how many times we encountered a full subbuffer, to aid
  * the user space app in telling how many lost events there were.
@@ -327,7 +369,8 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
        if (!buts->buf_size || !buts->buf_nr)
                return -EINVAL;
 
-       strcpy(buts->name, name);
+       strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
+       buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
 
        /*
         * some device names have larger paths - convert the slashes
@@ -346,6 +389,10 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
        if (!bt->sequence)
                goto err;
 
+       bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
+       if (!bt->msg_data)
+               goto err;
+
        ret = -ENOENT;
        dir = blk_create_tree(buts->name);
        if (!dir)
@@ -360,6 +407,10 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
        if (!bt->dropped_file)
                goto err;
 
+       bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
+       if (!bt->msg_file)
+               goto err;
+
        bt->rchan = relay_open("trace", dir, buts->buf_size,
                                buts->buf_nr, &blk_relay_callbacks, bt);
        if (!bt->rchan)
@@ -389,9 +440,12 @@ err:
        if (dir)
                blk_remove_tree(dir);
        if (bt) {
+               if (bt->msg_file)
+                       debugfs_remove(bt->msg_file);
                if (bt->dropped_file)
                        debugfs_remove(bt->dropped_file);
                free_percpu(bt->sequence);
+               free_percpu(bt->msg_data);
                if (bt->rchan)
                        relay_close(bt->rchan);
                kfree(bt);