Re: [PATCH 13/25] dmaengine: dw-edma: Stop checking debugfs_create_*() return value

Manivannan Sadhasivam
2022-03-24T18:13:15Z

On Thu, Mar 24, 2022 at 04:48:24AM +0300, Serge Semin wrote:
> First of all they never return NULL. So checking their return value for
> being not NULL just pointless. Secondly the DebugFS subsystem is designed
> in a way to be used as simple as possible. So if one of the
> debugfs_create_*() method in a hierarchy fails, the following methods will
> just silently return the passed erroneous parental dentry. Finally the
> code is supposed to be working no matter whether anything DebugFS-related
> fails. So in order to make code simpler and DebugFS-independent let's drop
> the debugfs_create_*() methods return value checking in the same way as
> the most of the kernel drivers do.
>
> Note in order to preserve some memory space we suggest to skip the DebugFS
> nodes initialization if the file system in unavailable.
>
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Thanks,
Man

> ---
> drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 20 +++++---------------
> 1 file changed, 5 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> index 12845a2dc016..808eed212be8 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> @@ -100,9 +100,8 @@ static void dw_edma_debugfs_create_x32(const struct debugfs_entries entries[],
> int i;
>
> for (i = 0; i < nr_entries; i++) {
> - if (!debugfs_create_file_unsafe(entries[i].name, 0444, dir,
> - entries[i].reg, &fops_x32))
> - break;
> + debugfs_create_file_unsafe(entries[i].name, 0444, dir,
> + entries[i].reg, &fops_x32);
> }
> }
>
> @@ -168,8 +167,6 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
> char name[16];
>
> regs_dir = debugfs_create_dir(WRITE_STR, dir);
> - if (!regs_dir)
> - return;
>
> nr_entries = ARRAY_SIZE(debugfs_regs);
> dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
> @@ -184,8 +181,6 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
> snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
>
> ch_dir = debugfs_create_dir(name, regs_dir);
> - if (!ch_dir)
> - return;
>
> dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].wr, ch_dir);
>
> @@ -237,8 +232,6 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
> char name[16];
>
> regs_dir = debugfs_create_dir(READ_STR, dir);
> - if (!regs_dir)
> - return;
>
> nr_entries = ARRAY_SIZE(debugfs_regs);
> dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
> @@ -253,8 +246,6 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
> snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
>
> ch_dir = debugfs_create_dir(name, regs_dir);
> - if (!ch_dir)
> - return;
>
> dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].rd, ch_dir);
>
> @@ -273,8 +264,6 @@ static void dw_edma_debugfs_regs(void)
> int nr_entries;
>
> regs_dir = debugfs_create_dir(REGISTERS_STR, dw->debugfs);
> - if (!regs_dir)
> - return;
>
> nr_entries = ARRAY_SIZE(debugfs_regs);
> dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
> @@ -285,6 +274,9 @@ static void dw_edma_debugfs_regs(void)
>
> void dw_edma_v0_debugfs_on(struct dw_edma_chip *chip)
> {
> + if (!debugfs_initialized())
> + return;
> +
> dw = chip->dw;
> if (!dw)
> return;
> @@ -294,8 +286,6 @@ void dw_edma_v0_debugfs_on(struct dw_edma_chip *chip)
> return;
>
> dw->debugfs = debugfs_create_dir(dw->name, NULL);
> - if (!dw->debugfs)
> - return;
>
> debugfs_create_u32("mf", 0444, dw->debugfs, &dw->chip->mf);
> debugfs_create_u16("wr_ch_cnt", 0444, dw->debugfs, &dw->wr_ch_cnt);
> --
> 2.35.1
>