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Commit 36c8fb2c authored by Thiago Jung Bauermann's avatar Thiago Jung Bauermann Committed by Michael Ellerman
Browse files

powerpc/perf/hv-24x7: Fix off-by-one error in request_buffer check 



request_buffer can hold 254 requests, so if it already has that number of
entries we can't add a new one.

Also, define constant to show where the number comes from.

Fixes: e3ee15dc ("powerpc/perf/hv-24x7: Define add_event_to_24x7_request()")
Reviewed-by: default avatarSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: default avatarThiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 12bf85a7

arch/powerpc/perf/hv-24x7.c

+5 −1
Original line number Diff line number Diff line
@@ -166,6 +166,10 @@ DEFINE_PER_CPU(struct hv_24x7_hw, hv_24x7_hw); 
DEFINE_PER_CPU(char, hv_24x7_reqb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);

DEFINE_PER_CPU(char, hv_24x7_resb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);



#define MAX_NUM_REQUESTS	((H24x7_DATA_BUFFER_SIZE -		       \

					sizeof(struct hv_24x7_request_buffer)) \

					/ sizeof(struct hv_24x7_request))



static char *event_name(struct hv_24x7_event_data *ev, int *len)

{

	*len = be16_to_cpu(ev->event_name_len) - 2;
@@ -1107,7 +1111,7 @@ static int add_event_to_24x7_request(struct perf_event *event, 
	int i;

	struct hv_24x7_request *req;



	if (request_buffer->num_requests > 254) {

	if (request_buffer->num_requests >= MAX_NUM_REQUESTS) {

		pr_devel("Too many requests for 24x7 HCALL %d\n",

				request_buffer->num_requests);

		return -EINVAL;