shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-04-21 04:51:09 +09:00
Code Issues Packages Projects Releases Wiki Activity

USB: gadget: f_mass_storage: Flush writes after every 4 MB.

Browse Source 
This avoids excessive caching at the block level layer when copying large
files to the storage device.

Signed-off-by: Mike Lockwood <lockwood@android.com>
This commit is contained in:
Mike Lockwood
2010-03-12 11:01:05 -05:00
committed by Colin Cross
parent 82c7dd9e74
commit b0d8ef8a45
1 changed files with 13 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/usb/gadget/f_mass_storage_tmp.c
View File

@@ -79,6 +79,9 @@
#define BULK_BUFFER_SIZE 4096
/* flush after every 4 meg of writes to avoid excessive block level caching */
#define MAX_UNFLUSHED_BYTES (4 * 1024 * 1024)
/*-------------------------------------------------------------------------*/
#define DRIVER_NAME "usb_mass_storage"
@@ -226,6 +229,7 @@ struct lun {
struct file *filp;
loff_t file_length;
loff_t num_sectors;
unsigned int unflushed_bytes;
unsigned int ro : 1;
unsigned int prevent_medium_removal : 1;
@@ -392,7 +396,7 @@ static struct fsg_dev *the_fsg;
static void close_backing_file(struct fsg_dev *fsg, struct lun *curlun);
static void close_all_backing_files(struct fsg_dev *fsg);
static int fsync_sub(struct lun *curlun);
/*-------------------------------------------------------------------------*/
@@ -1039,6 +1043,13 @@ static int do_write(struct fsg_dev *fsg)
amount_left_to_write -= nwritten;
fsg->residue -= nwritten;
#ifdef MAX_UNFLUSHED_BYTES
curlun->unflushed_bytes += nwritten;
if (curlun->unflushed_bytes >= MAX_UNFLUSHED_BYTES) {
fsync_sub(curlun);
curlun->unflushed_bytes = 0;
}
#endif
/* If an error occurred, report it and its position */
if (nwritten < amount) {
curlun->sense_data = SS_WRITE_ERROR;
@@ -2515,6 +2526,7 @@ static int open_backing_file(struct fsg_dev *fsg, struct lun *curlun,
curlun->ro = ro;
curlun->filp = filp;
curlun->file_length = size;
curlun->unflushed_bytes = 0;
curlun->num_sectors = num_sectors;
LDBG(curlun, "open backing file: %s size: %lld num_sectors: %lld\n",
filename, size, num_sectors);