Messages in this thread | | | Date | Wed, 28 Jan 2015 00:46:59 +0100 | From | Richard Weinberger <> | Subject | Re: [PATCH 1/2 v2] UBI: Add initial support for scatter gather |
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Am 28.01.2015 um 00:36 schrieb Ezequiel Garcia: > On 01/10/2015 06:52 PM, Richard Weinberger wrote: >> Adds a new set of functions to deal with scatter gather. >> ubi_eba_read_leb_sg() will read from a LEB into a scatter gather list. >> The new data structure struct ubi_sgl will be used within UBI to >> hold the scatter gather list itself and metadata to have a cursor >> within the list. >> >> Signed-off-by: Richard Weinberger <richard@nod.at> >> Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> > > Three nitpicks below, and my > > Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> > >> --- >> drivers/mtd/ubi/eba.c | 56 +++++++++++++++++++++++++++++ >> drivers/mtd/ubi/kapi.c | 95 +++++++++++++++++++++++++++++++++++++++++-------- >> drivers/mtd/ubi/ubi.h | 3 ++ >> include/linux/mtd/ubi.h | 46 ++++++++++++++++++++++++ >> 4 files changed, 185 insertions(+), 15 deletions(-) >> >> diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c >> index b698534..0aaf707 100644 >> --- a/drivers/mtd/ubi/eba.c >> +++ b/drivers/mtd/ubi/eba.c >> @@ -481,6 +481,62 @@ out_unlock: >> } >> >> /** >> + * ubi_eba_read_leb_sg - read data into a scatter gather list. >> + * @ubi: UBI device description object >> + * @vol: volume description object >> + * @lnum: logical eraseblock number >> + * @sgl: UBI scatter gather list to store the read data >> + * @offset: offset from where to read >> + * @len: how many bytes to read >> + * @check: data CRC check flag >> + * >> + * This function works exactly like ubi_eba_read_leb(). But instead of >> + * storing the read data into a buffer it writes to an UBI scatter gather >> + * list. >> + */ >> +int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol, >> + struct ubi_sgl *sgl, int lnum, int offset, int len, >> + int check) >> +{ >> + int to_read; >> + int ret; >> + struct scatterlist *sg; >> + >> + for (;;) { >> + ubi_assert(sgl->list_pos < UBI_MAX_SG_COUNT); >> + sg = &sgl->sg[sgl->list_pos]; >> + if (len < sg->length - sgl->page_pos) >> + to_read = len; >> + else >> + to_read = sg->length - sgl->page_pos; >> + >> + ret = ubi_eba_read_leb(ubi, vol, lnum, >> + sg_virt(sg) + sgl->page_pos, offset, >> + to_read, check); >> + if (ret < 0) >> + goto out; > > Matter of taste, but isn't it better to just return here?
After dealing with a lot of nasty bugs in error paths in other projects I've started using the principle of a single function exit path. But in this case a "return ret;" is also perfectly fine as the "out" label does no cleanup.
Will fix before pushing.
>> + >> + offset += to_read; >> + len -= to_read; >> + if (!len) { >> + sgl->page_pos += to_read; >> + if (sgl->page_pos == sg->length) { >> + sgl->list_pos++; >> + sgl->page_pos = 0; >> + } >> + >> + break; >> + } >> + >> + sgl->list_pos++; >> + sgl->page_pos = 0; >> + } >> + >> +out: >> + return ret; >> +} >> + >> +/** >> * recover_peb - recover from write failure. >> * @ubi: UBI device description object >> * @pnum: the physical eraseblock to recover >> diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c >> index f3bab66..d0055a2 100644 >> --- a/drivers/mtd/ubi/kapi.c >> +++ b/drivers/mtd/ubi/kapi.c >> @@ -355,6 +355,43 @@ void ubi_close_volume(struct ubi_volume_desc *desc) >> EXPORT_SYMBOL_GPL(ubi_close_volume); >> >> /** >> + * leb_read_sanity_check - does sanity checks on read requests. >> + * @desc: volume descriptor >> + * @lnum: logical eraseblock number to read from >> + * @offset: offset within the logical eraseblock to read from >> + * @len: how many bytes to read >> + * >> + * This function is used by ubi_leb_read() and ubi_leb_read_sg() >> + * to perfrom sanity checks. > > s/perfrom/perform
Thx.
> >> + */ >> +static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum, >> + int offset, int len) >> +{ >> + struct ubi_volume *vol = desc->vol; >> + struct ubi_device *ubi = vol->ubi; >> + int vol_id = vol->vol_id; >> + >> + if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 || >> + lnum >= vol->used_ebs || offset < 0 || len < 0 || >> + offset + len > vol->usable_leb_size) >> + return -EINVAL; >> + >> + if (vol->vol_type == UBI_STATIC_VOLUME) { >> + if (vol->used_ebs == 0) >> + /* Empty static UBI volume */ >> + return 0; >> + if (lnum == vol->used_ebs - 1 && >> + offset + len > vol->last_eb_bytes) >> + return -EINVAL; >> + } >> + >> + if (vol->upd_marker) >> + return -EBADF; >> + >> + return 0; >> +} >> + >> +/** >> * ubi_leb_read - read data. >> * @desc: volume descriptor >> * @lnum: logical eraseblock number to read from >> @@ -390,22 +427,10 @@ int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset, >> >> dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset); >> >> - if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 || >> - lnum >= vol->used_ebs || offset < 0 || len < 0 || >> - offset + len > vol->usable_leb_size) >> - return -EINVAL; >> - >> - if (vol->vol_type == UBI_STATIC_VOLUME) { >> - if (vol->used_ebs == 0) >> - /* Empty static UBI volume */ >> - return 0; >> - if (lnum == vol->used_ebs - 1 && >> - offset + len > vol->last_eb_bytes) >> - return -EINVAL; >> - } >> + err = leb_read_sanity_check(desc, lnum, offset, len); >> + if (err < 0) >> + return err; >> >> - if (vol->upd_marker) >> - return -EBADF; >> if (len == 0) >> return 0; >> >> @@ -419,6 +444,46 @@ int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset, >> } >> EXPORT_SYMBOL_GPL(ubi_leb_read); >> >> + >> +/** >> + * ubi_leb_read_sg - read data into a scatter gather list. >> + * @desc: volume descriptor >> + * @lnum: logical eraseblock number to read from >> + * @buf: buffer where to store the read data >> + * @offset: offset within the logical eraseblock to read from >> + * @len: how many bytes to read >> + * @check: whether UBI has to check the read data's CRC or not. >> + * >> + * This function works exactly like ubi_leb_read_sg(). But instead of >> + * storing the read data into a buffer it writes to an UBI scatter gather >> + * list. >> + */ >> +int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl, >> + int offset, int len, int check) >> +{ >> + struct ubi_volume *vol = desc->vol; >> + struct ubi_device *ubi = vol->ubi; >> + int err, vol_id = vol->vol_id; >> + >> + dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset); >> + >> + err = leb_read_sanity_check(desc, lnum, offset, len); >> + if (err < 0) >> + return err; >> + >> + if (len == 0) >> + return 0; >> + >> + err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check); >> + if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) { >> + ubi_warn(ubi, "mark volume %d as corrupted", vol_id); >> + vol->corrupted = 1; >> + } >> + >> + return err; >> +} >> +EXPORT_SYMBOL_GPL(ubi_leb_read_sg); >> + >> /** >> * ubi_leb_write - write data. >> * @desc: volume descriptor >> diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h >> index ee7ac0b..a5283cf 100644 >> --- a/drivers/mtd/ubi/ubi.h >> +++ b/drivers/mtd/ubi/ubi.h >> @@ -791,6 +791,9 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol, >> int lnum); >> int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, >> void *buf, int offset, int len, int check); >> +int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol, >> + struct ubi_sgl *sgl, int lnum, int offset, int len, >> + int check); >> int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, >> const void *buf, int offset, int len); >> int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol, >> diff --git a/include/linux/mtd/ubi.h b/include/linux/mtd/ubi.h >> index c3918a0..3d5916d 100644 >> --- a/include/linux/mtd/ubi.h >> +++ b/include/linux/mtd/ubi.h >> @@ -23,11 +23,16 @@ >> >> #include <linux/ioctl.h> >> #include <linux/types.h> >> +#include <linux/scatterlist.h> >> #include <mtd/ubi-user.h> >> >> /* All voumes/LEBs */ >> #define UBI_ALL -1 >> >> +/* Maximum number of scatter gather list entries, >> + * we use only 64 to have a lower memory foot print. */ > > Multilines comments style is: > > /* > * > */
Correct. I wonder why checkpatch.pl did not bark on that.
Thanks, //richard
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