* [PATCH] mtd: core: allow mask_flags to be set for mtd_add_partition
@ 2019-11-26 21:25 Bruno Pena
2020-02-05 8:31 ` Rafał Miłecki
0 siblings, 1 reply; 4+ messages in thread
From: Bruno Pena @ 2019-11-26 21:25 UTC (permalink / raw)
To: linux-mtd; +Cc: Bruno Pena
This patchs makes it possible to mask certain flags for new partitions (e.g. to make them read-only).
The change consists in the addition of a new argument "mask_flags" to "mtd_add_partition" that is passed on to the "allocate_partition".
Signed-off-by: Bruno Pena <brunompena@gmail.com>
---
drivers/mtd/mtdchar.c | 5 ++++-
drivers/mtd/mtdpart.c | 3 ++-
include/linux/mtd/partitions.h | 2 +-
3 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 0238952..0c0a6f2 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -583,7 +583,10 @@ static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
/* Sanitize user input */
p.devname[BLKPG_DEVNAMELTH - 1] = '\0';
- return mtd_add_partition(mtd, p.devname, p.start, p.length);
+ /* No mtd flag masking required */
+ uint32_t mask_flags = 0;
+
+ return mtd_add_partition(mtd, p.devname, p.start, p.length, mask_flags);
case BLKPG_DEL_PARTITION:
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index b6af41b..66675a4 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -588,7 +588,7 @@ static int mtd_add_partition_attrs(struct mtd_part *new)
}
int mtd_add_partition(struct mtd_info *parent, const char *name,
- long long offset, long long length)
+ long long offset, long long length, uint32_t mask_flags)
{
struct mtd_partition part;
struct mtd_part *new;
@@ -609,6 +609,7 @@ int mtd_add_partition(struct mtd_info *parent, const char *name,
part.name = name;
part.size = length;
part.offset = offset;
+ part.mask_flags = mask_flags;
new = allocate_partition(parent, &part, -1, offset);
if (IS_ERR(new))
diff --git a/include/linux/mtd/partitions.h b/include/linux/mtd/partitions.h
index 11cb0c5..1a0deeb 100644
--- a/include/linux/mtd/partitions.h
+++ b/include/linux/mtd/partitions.h
@@ -107,7 +107,7 @@ extern void deregister_mtd_parser(struct mtd_part_parser *parser);
int mtd_is_partition(const struct mtd_info *mtd);
int mtd_add_partition(struct mtd_info *master, const char *name,
- long long offset, long long length);
+ long long offset, long long length, uint32_t mask_flags);
int mtd_del_partition(struct mtd_info *master, int partno);
uint64_t mtd_get_device_size(const struct mtd_info *mtd);
--
2.7.4
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http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] mtd: core: allow mask_flags to be set for mtd_add_partition
2019-11-26 21:25 [PATCH] mtd: core: allow mask_flags to be set for mtd_add_partition Bruno Pena
@ 2020-02-05 8:31 ` Rafał Miłecki
2020-02-05 17:34 ` Bruno Pena
0 siblings, 1 reply; 4+ messages in thread
From: Rafał Miłecki @ 2020-02-05 8:31 UTC (permalink / raw)
To: Bruno Pena, linux-mtd
Hi,
On 26.11.2019 22:25, Bruno Pena wrote:
> This patchs makes it possible to mask certain flags for new partitions (e.g. to make them read-only).
> The change consists in the addition of a new argument "mask_flags" to "mtd_add_partition" that is passed on to the "allocate_partition".
Your description answers "what?" but not "why?".
This patch adds a new function argument that is never used. This seems
quite pointless.
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mtd: core: allow mask_flags to be set for mtd_add_partition
2020-02-05 8:31 ` Rafał Miłecki
@ 2020-02-05 17:34 ` Bruno Pena
2020-02-06 13:46 ` Rafał Miłecki
0 siblings, 1 reply; 4+ messages in thread
From: Bruno Pena @ 2020-02-05 17:34 UTC (permalink / raw)
To: linux-mtd
Hi Rafał,
A possible use case is mentioned on the description "mask certain
flags for new partitions (e.g. to make them read-only)" - I believe
this answers your "why?" question.
As for your comment about usefulness, you are very well aware this
comes from the OpenWrt pull request 2535 [1] where this new argument
is used.
The only reason why the full patch was not sent here is because it
depends on OpenWrt specific code [2] [3] that is yet to be merged on
the kernel.
For this reason - and as requested on OpenWrt - I decided to submit an
enabler patch for the kernel exported API mtd_add_partition.
[1] https://github.com/openwrt/openwrt/pull/2535
[2] https://github.com/openwrt/openwrt/blob/master/target/linux/generic/pending-4.14/401-mtd-add-support-for-different-partition-parser-types.patch
[3] https://github.com/openwrt/openwrt/blob/master/target/linux/generic/pending-4.19/401-mtd-add-support-for-different-partition-parser-types.patch
Best regards,
Bruno Pena
On Wed, Feb 5, 2020 at 9:31 AM Rafał Miłecki <zajec5@gmail.com> wrote:
>
> Hi,
>
> On 26.11.2019 22:25, Bruno Pena wrote:
> > This patchs makes it possible to mask certain flags for new partitions (e.g. to make them read-only).
> > The change consists in the addition of a new argument "mask_flags" to "mtd_add_partition" that is passed on to the "allocate_partition".
>
> Your description answers "what?" but not "why?".
>
> This patch adds a new function argument that is never used. This seems
> quite pointless.
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mtd: core: allow mask_flags to be set for mtd_add_partition
2020-02-05 17:34 ` Bruno Pena
@ 2020-02-06 13:46 ` Rafał Miłecki
0 siblings, 0 replies; 4+ messages in thread
From: Rafał Miłecki @ 2020-02-06 13:46 UTC (permalink / raw)
To: Bruno Pena; +Cc: linux-mtd
On Wed, 5 Feb 2020 at 18:35, Bruno Pena <brunompena@gmail.com> wrote:
> A possible use case is mentioned on the description "mask certain
> flags for new partitions (e.g. to make them read-only)" - I believe
> this answers your "why?" question.
> As for your comment about usefulness, you are very well aware this
> comes from the OpenWrt pull request 2535 [1] where this new argument
> is used.
> The only reason why the full patch was not sent here is because it
> depends on OpenWrt specific code [2] [3] that is yet to be merged on
> the kernel.
> For this reason - and as requested on OpenWrt - I decided to submit an
> enabler patch for the kernel exported API mtd_add_partition.
The problem with this patch is it adds "a possible" use case and not a
real one. It describes ability to "mask certain flags" but it doesn't
explain why/when it should be needed. You most likely can't do that as
there isn't any *in-kernel* need for that.
As much as I love upstreaming OpenWrt downstream patches I think this
change should be rejected. Kernel mustn't care about providing
required API for all downstream changes of various projects. If there
is some downstream code that needs a new function argument you should
upstream both. From kernel perspective there is no need for this
change as it adds unused code.
--
Rafał
On Wed, 5 Feb 2020 at 18:35, Bruno Pena <brunompena@gmail.com> wrote:
>
> Hi Rafał,
>
> A possible use case is mentioned on the description "mask certain
> flags for new partitions (e.g. to make them read-only)" - I believe
> this answers your "why?" question.
> As for your comment about usefulness, you are very well aware this
> comes from the OpenWrt pull request 2535 [1] where this new argument
> is used.
> The only reason why the full patch was not sent here is because it
> depends on OpenWrt specific code [2] [3] that is yet to be merged on
> the kernel.
> For this reason - and as requested on OpenWrt - I decided to submit an
> enabler patch for the kernel exported API mtd_add_partition.
>
> [1] https://github.com/openwrt/openwrt/pull/2535
> [2] https://github.com/openwrt/openwrt/blob/master/target/linux/generic/pending-4.14/401-mtd-add-support-for-different-partition-parser-types.patch
> [3] https://github.com/openwrt/openwrt/blob/master/target/linux/generic/pending-4.19/401-mtd-add-support-for-different-partition-parser-types.patch
>
> Best regards,
> Bruno Pena
>
>
> On Wed, Feb 5, 2020 at 9:31 AM Rafał Miłecki <zajec5@gmail.com> wrote:
> >
> > Hi,
> >
> > On 26.11.2019 22:25, Bruno Pena wrote:
> > > This patchs makes it possible to mask certain flags for new partitions (e.g. to make them read-only).
> > > The change consists in the addition of a new argument "mask_flags" to "mtd_add_partition" that is passed on to the "allocate_partition".
> >
> > Your description answers "what?" but not "why?".
> >
> > This patch adds a new function argument that is never used. This seems
> > quite pointless.
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
--
Rafał
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
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2019-11-26 21:25 [PATCH] mtd: core: allow mask_flags to be set for mtd_add_partition Bruno Pena
2020-02-05 8:31 ` Rafał Miłecki
2020-02-05 17:34 ` Bruno Pena
2020-02-06 13:46 ` Rafał Miłecki
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