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Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r--kernel/trace/trace.c36
1 files changed, 21 insertions, 15 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 9d28476..1ce5dc6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3277,19 +3277,13 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
info->tr = &global_trace;
info->cpu = cpu;
- info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
+ info->spare = NULL;
/* Force reading ring buffer for first read */
info->read = (unsigned int)-1;
- if (!info->spare)
- goto out;
filp->private_data = info;
- return 0;
-
- out:
- kfree(info);
- return -ENOMEM;
+ return nonseekable_open(inode, filp);
}
static ssize_t
@@ -3304,6 +3298,11 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
if (!count)
return 0;
+ if (!info->spare)
+ info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
+ if (!info->spare)
+ return -ENOMEM;
+
/* Do we have previous read data to read? */
if (info->read < PAGE_SIZE)
goto read;
@@ -3342,7 +3341,8 @@ static int tracing_buffers_release(struct inode *inode, struct file *file)
{
struct ftrace_buffer_info *info = file->private_data;
- ring_buffer_free_read_page(info->tr->buffer, info->spare);
+ if (info->spare)
+ ring_buffer_free_read_page(info->tr->buffer, info->spare);
kfree(info);
return 0;
@@ -3428,14 +3428,19 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
int size, i;
size_t ret;
- /*
- * We can't seek on a buffer input
- */
- if (unlikely(*ppos))
- return -ESPIPE;
+ if (*ppos & (PAGE_SIZE - 1)) {
+ WARN_ONCE(1, "Ftrace: previous read must page-align\n");
+ return -EINVAL;
+ }
+ if (len & (PAGE_SIZE - 1)) {
+ WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
+ if (len < PAGE_SIZE)
+ return -EINVAL;
+ len &= PAGE_MASK;
+ }
- for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) {
+ for (i = 0; i < PIPE_BUFFERS && len; i++, len -= PAGE_SIZE) {
struct page *page;
int r;
@@ -3474,6 +3479,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
spd.partial[i].offset = 0;
spd.partial[i].private = (unsigned long)ref;
spd.nr_pages++;
+ *ppos += PAGE_SIZE;
}
spd.nr_pages = i;
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