Eric Lee / smarc-fsl-linux-kernel

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Commit b003f4e171304234eae9cc11c9fd7f1cbaaf0d6b

Authored by Jan Kiszka
Committed by David S. Miller
1 parent 1e253c3b8a

CAPI: Silence lockdep warning on get_capi_appl_by_nr usage 

As long as we hold capi_controller_lock, we can safely access
capi_applications without RCU protection as no one can modify the
application list underneath us. Introduce an RCU-free
__get_capi_appl_by_nr for this purpose. This silences lockdep warnings
on suspicious rcu_dereference usage.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Showing 1 changed file with 14 additions and 5 deletions Side-by-side Diff

drivers/isdn/capi/kcapi.c
Diff comments   View file @ b003f4e
... ... @@ -98,6 +98,16 @@
98 98 return capi_controller[contr - 1];
99 99 }
100 100  
  101 +static inline struct capi20_appl *__get_capi_appl_by_nr(u16 applid)
  102 +{
  103 + lockdep_assert_held(&capi_controller_lock);
  104 +
  105 + if (applid - 1 >= CAPI_MAXAPPL)
  106 + return NULL;
  107 +
  108 + return capi_applications[applid - 1];
  109 +}
  110 +
101 111 static inline struct capi20_appl *get_capi_appl_by_nr(u16 applid)
102 112 {
103 113 if (applid - 1 >= CAPI_MAXAPPL)
... ... @@ -185,10 +195,9 @@
185 195 ctr->state = CAPI_CTR_RUNNING;
186 196  
187 197 for (applid = 1; applid <= CAPI_MAXAPPL; applid++) {
188   - ap = get_capi_appl_by_nr(applid);
189   - if (!ap)
190   - continue;
191   - register_appl(ctr, applid, &ap->rparam);
  198 + ap = __get_capi_appl_by_nr(applid);
  199 + if (ap)
  200 + register_appl(ctr, applid, &ap->rparam);
192 201 }
193 202  
194 203 wake_up_interruptible_all(&ctr->state_wait_queue);
... ... @@ -215,7 +224,7 @@
215 224 memset(ctr->serial, 0, sizeof(ctr->serial));
216 225  
217 226 for (applid = 1; applid <= CAPI_MAXAPPL; applid++) {
218   - ap = get_capi_appl_by_nr(applid);
  227 + ap = __get_capi_appl_by_nr(applid);
219 228 if (ap)
220 229 capi_ctr_put(ctr);
221 230 }