Commit 5f492a7a authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Martin K. Petersen
Browse files

scsi: smartpqi: Replace one-element array with flexible-array member 

There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code
should always use "flexible array members"[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].

Refactor the code a bit according to the use of a flexible-array member in
struct pqi_event_config instead of a one-element array, and use the
struct_size() helper.

This helps with the ongoing efforts to globally enable -Warray-bounds and
get us closer to being able to tighten the FORTIFY_SOURCE routines on
memcpy().

This issue was found with the help of Coccinelle and audited and fixed,
manually.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/109
Link: https://lore.kernel.org/r/20210810210741.GA58765@embeddedor


Signed-off-by: default avatarGustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 0f99792c

drivers/scsi/smartpqi/smartpqi.h

+1 −1
Original line number Diff line number Diff line
@@ -415,7 +415,7 @@ struct pqi_event_config { 
	u8	reserved[2];

	u8	num_event_descriptors;

	u8	reserved1;

	struct pqi_event_descriptor descriptors[1];

	struct pqi_event_descriptor descriptors[];

};



#define PQI_MAX_EVENT_DESCRIPTORS	255

drivers/scsi/smartpqi/smartpqi_init.c

+1 −2
Original line number Diff line number Diff line
@@ -4741,8 +4741,7 @@ static int pqi_create_queues(struct pqi_ctrl_info *ctrl_info) 
}



#define PQI_REPORT_EVENT_CONFIG_BUFFER_LENGTH	\

	(offsetof(struct pqi_event_config, descriptors) + \

	(PQI_MAX_EVENT_DESCRIPTORS * sizeof(struct pqi_event_descriptor)))

	struct_size((struct pqi_event_config *)0, descriptors, PQI_MAX_EVENT_DESCRIPTORS)



static int pqi_configure_events(struct pqi_ctrl_info *ctrl_info,

	bool enable_events)