From: Markus Pargmann <mpa@pengutronix.de>
To: barebox@lists.infradead.org
Cc: mgr@pengutronix.de
Subject: [PATCH v2 5/6] state: backend_storage_direct: also use cached data on write
Date: Fri, 24 Jun 2016 12:06:01 +0200 [thread overview]
Message-ID: <1466762762-15212-6-git-send-email-mpa@pengutronix.de> (raw)
In-Reply-To: <1466762762-15212-1-git-send-email-mpa@pengutronix.de>
From: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
---
common/state/backend_bucket_direct.c | 55 ++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
diff --git a/common/state/backend_bucket_direct.c b/common/state/backend_bucket_direct.c
index 08892f001e25..772267f6dc1d 100644
--- a/common/state/backend_bucket_direct.c
+++ b/common/state/backend_bucket_direct.c
@@ -29,6 +29,10 @@ struct state_backend_storage_bucket_direct {
int fd;
+ /* Cached data of the last read/write */
+ u8 *current_data;
+ ssize_t current_data_len;
+
struct device_d *dev;
};
@@ -99,6 +103,29 @@ static int state_backend_bucket_direct_read(struct state_backend_storage_bucket
return 0;
}
+
+static int state_backend_bucket_direct_fill_cache(
+ struct state_backend_storage_bucket *bucket)
+{
+ struct state_backend_storage_bucket_direct *direct =
+ get_bucket_direct(bucket);
+ ssize_t read_len;
+ uint8_t *buf;
+ int ret;
+
+ ret = state_backend_bucket_direct_read(bucket, &buf, &read_len);
+ if (ret < 0) {
+ dev_err(direct->dev, "Failed to read from file, %d\n", ret);
+ free(buf);
+ return ret;
+ }
+
+ direct->current_data = buf;
+ direct->current_data_len = read_len;
+
+ return 0;
+}
+
static int state_backend_bucket_direct_write(struct state_backend_storage_bucket
*bucket, const uint8_t * buf,
ssize_t len)
@@ -111,6 +138,11 @@ static int state_backend_bucket_direct_write(struct state_backend_storage_bucket
if (direct->max_size && len > direct->max_size)
return -E2BIG;
+ /* Nothing in cache? Then read to see what is on the device currently */
+ if (!direct->current_data) {
+ state_backend_bucket_direct_fill_cache(bucket);
+ }
+
ret = lseek(direct->fd, direct->offset, SEEK_SET);
if (ret < 0) {
dev_err(direct->dev, "Failed to seek file, %d\n", ret);
@@ -119,6 +151,26 @@ static int state_backend_bucket_direct_write(struct state_backend_storage_bucket
meta.magic = direct_magic;
meta.written_length = len;
+
+ /*
+ * If we would write the same data that is currently on the device, we
+ * can return successfully without writing.
+ * Note that the cache may still be empty if the storage is empty or
+ * errors occured.
+ */
+ if (direct->current_data) {
+ dev_dbg(direct->dev, "Comparing cached data, writing %zd bytes, cached %zd bytes\n",
+ len, direct->current_data_len);
+ if (len == direct->current_data_len &&
+ !memcmp(direct->current_data, buf, len)) {
+ dev_dbg(direct->dev, "Data already on device, not writing again\n");
+ return ret;
+ } else {
+ free(direct->current_data);
+ direct->current_data = NULL;
+ }
+ }
+
ret = write_full(direct->fd, &meta, sizeof(meta));
if (ret < 0) {
dev_err(direct->dev, "Failed to write metadata to file, %d\n", ret);
@@ -147,6 +199,9 @@ static void state_backend_bucket_direct_free(struct
struct state_backend_storage_bucket_direct *direct =
get_bucket_direct(bucket);
+ if (direct->current_data)
+ free(direct->current_data);
+
close(direct->fd);
free(direct);
}
--
2.8.1
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next prev parent reply other threads:[~2016-06-24 10:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-24 10:05 [PATCH v2 0/6] state: Refactor backend Markus Pargmann
2016-06-24 10:05 ` [PATCH v2 1/6] libfile: Change write_full to be have const buf Markus Pargmann
2016-06-24 10:05 ` [PATCH v2 2/6] state: Refactor state framework Markus Pargmann
2016-06-24 10:05 ` [PATCH v2 3/6] docs: Add/Update state documentation Markus Pargmann
2016-06-24 10:06 ` [PATCH v2 4/6] state: also append backend storage stridesize Markus Pargmann
2016-06-24 10:06 ` Markus Pargmann [this message]
2016-06-28 6:18 ` [PATCH v2 5/6] state: backend_storage_direct: also use cached data on write Sascha Hauer
2016-06-28 6:55 ` Michael Grzeschik
2016-06-29 5:56 ` Markus Pargmann
2016-06-24 10:06 ` [PATCH v2 6/6] barebox-state: handle flush errno correctly Markus Pargmann
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