Re: [PATCH] mmc_spi: do propper retry managment in the block layer - 3rd try
- From: Matt Fleming <matt@xxxxxxxxxxxxxxxxx>
- Date: Sat, 30 May 2009 23:16:13 +0100
On Thu, May 28, 2009 at 11:52:26AM +0200, Wolfgang Mües wrote:
So somewhere I will need to have an error code filter based on the issued
command (class). Should this be in the driver(s)? Or should it be at the
location of the caller, in block.c?
It should be in the function/file that makes the most sense.
The advantages of putting it in block.c is that
a) The command (class) is typically implicit given in the function, and no
need for a switch() statement.
b) Only one handling for different drivers, not scattered through all(?) host
drivers.
You know what, I was going to say that only block transaction stuff is
in block.c, but that's not true, there's loads of MMC protocol
knowledge in there too. I don't think there's a better place than
mmc/drivers/card/block.c, currently.
I would expect all this error handling and intimate knowledge of the
MMC/SD protocol to be in drivers/mmc/core, but that's not the
case. Which just seems strange to me.
I must admit that I have difficulties to see a clear layering violation.
There is no clear definition of which error codes should be reported to the
block layer. There is only a short list of codes with special meaning, but
not a full list of all used codes.
And some drivers are reporting codes like ENOMEM etc...
I see that Pierre wants to have a more smaller interface between drivers and
the upper layer, reporting only classes of errors, to have a more smaller and
cleaner code in the upper layer. But I think that this is a patch of its own,
and not in the context of the retry patch.
I agree. That could be a separate patch.
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- Re: [PATCH] mmc_spi: do propper retry managment in the block layer - 3rd try
- From: Matt Fleming
- Re: [PATCH] mmc_spi: do propper retry managment in the block layer - 3rd try
- From: Wolfgang Mües
- Re: [PATCH] mmc_spi: do propper retry managment in the block layer - 3rd try
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