| Message ID | 20210807214538.14484-3-sean@mess.org |
|---|---|
| State | Accepted |
| Headers | show |
| Series | Fix various issues with RFD and FTLs | expand |
On Sat, 2021-08-07 at 21:45:35 UTC, Sean Young wrote: > I proposed this change 16 years ago before discard was a feature in > the block layer: https://lwn.net/Articles/162776/ > > Now that the block layer has discard, we can finally merge this change. > > Discard is also known as trim. By implementing discard, both fstrim and > the discard filesystem option can be used. > > Implementing discard in the ftl means that when files are removed, there > is less data in the ftl mapping. This means less stuff to move around for > erasing and also less erasing to do; this means improved wear levelling > and improved performance. > > Signed-off-by: Sean Young <sean@mess.org> Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks. Miquel
diff --git a/drivers/mtd/rfd_ftl.c b/drivers/mtd/rfd_ftl.c index 7b243f2b2fa3..7f5f6d247cae 100644 --- a/drivers/mtd/rfd_ftl.c +++ b/drivers/mtd/rfd_ftl.c @@ -705,6 +705,34 @@ static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char * return rc; } +static int rfd_ftl_discardsect(struct mtd_blktrans_dev *dev, + unsigned long sector, unsigned int nr_sects) +{ + struct partition *part = (struct partition *)dev; + u_long addr; + int rc; + + while (nr_sects) { + if (sector >= part->sector_count) + return -EIO; + + addr = part->sector_map[sector]; + + if (addr != -1) { + rc = mark_sector_deleted(part, addr); + if (rc) + return rc; + + part->sector_map[sector] = -1; + } + + sector++; + nr_sects--; + } + + return 0; +} + static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo) { struct partition *part = (struct partition*)dev; @@ -786,6 +814,7 @@ static struct mtd_blktrans_ops rfd_ftl_tr = { .readsect = rfd_ftl_readsect, .writesect = rfd_ftl_writesect, + .discard = rfd_ftl_discardsect, .getgeo = rfd_ftl_getgeo, .add_mtd = rfd_ftl_add_mtd, .remove_dev = rfd_ftl_remove_dev,
I proposed this change 16 years ago before discard was a feature in the block layer: https://lwn.net/Articles/162776/ Now that the block layer has discard, we can finally merge this change. Discard is also known as trim. By implementing discard, both fstrim and the discard filesystem option can be used. Implementing discard in the ftl means that when files are removed, there is less data in the ftl mapping. This means less stuff to move around for erasing and also less erasing to do; this means improved wear levelling and improved performance. Signed-off-by: Sean Young <sean@mess.org> --- drivers/mtd/rfd_ftl.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)