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Diffstat (limited to 'kernel/printk/printk_ringbuffer.c')
-rw-r--r--kernel/printk/printk_ringbuffer.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c
index f5a8bb606f..88e8f3a619 100644
--- a/kernel/printk/printk_ringbuffer.c
+++ b/kernel/printk/printk_ringbuffer.c
@@ -1034,9 +1034,13 @@ static char *data_alloc(struct printk_ringbuffer *rb, unsigned int size,
unsigned long next_lpos;
if (size == 0) {
- /* Specify a data-less block. */
- blk_lpos->begin = NO_LPOS;
- blk_lpos->next = NO_LPOS;
+ /*
+ * Data blocks are not created for empty lines. Instead, the
+ * reader will recognize these special lpos values and handle
+ * it appropriately.
+ */
+ blk_lpos->begin = EMPTY_LINE_LPOS;
+ blk_lpos->next = EMPTY_LINE_LPOS;
return NULL;
}
@@ -1214,10 +1218,18 @@ static const char *get_data(struct prb_data_ring *data_ring,
/* Data-less data block description. */
if (BLK_DATALESS(blk_lpos)) {
- if (blk_lpos->begin == NO_LPOS && blk_lpos->next == NO_LPOS) {
+ /*
+ * Records that are just empty lines are also valid, even
+ * though they do not have a data block. For such records
+ * explicitly return empty string data to signify success.
+ */
+ if (blk_lpos->begin == EMPTY_LINE_LPOS &&
+ blk_lpos->next == EMPTY_LINE_LPOS) {
*data_size = 0;
return "";
}
+
+ /* Data lost, invalid, or otherwise unavailable. */
return NULL;
}