| Message ID | 20181004094113.5492-1-yuehaibing@huawei.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [v2,-next] powerpc/pseries/memory-hotplug: Fix return value type of find_aa_index | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | next/apply_patch Successfully applied |
| snowpatch_ozlabs/checkpatch | success | Test checkpatch on branch next |
| snowpatch_ozlabs/build-ppc64le | warning | Test build-ppc64le on branch next |
| snowpatch_ozlabs/build-ppc64be | success | Test build-ppc64be on branch next |
| snowpatch_ozlabs/build-ppc64e | success | Test build-ppc64e on branch next |
| snowpatch_ozlabs/build-ppc32 | success | Test build-ppc32 on branch next |
YueHaibing <yuehaibing@huawei.com> writes: > 'aa_index' is defined as an unsigned value, but find_aa_index > may return -1 when dlpar_clone_property fails. So we use an rc > value to track the validation of finding the aa_index instead > of the 'aa_index' value itself > > Fixes: c05a5a40969e ("powerpc/pseries: Dynamic add entires to associativity lookup array") > Signed-off-by: YueHaibing <yuehaibing@huawei.com> > --- > v2: use 'rc' track the validation of aa_index Thanks for sending a v2, some more comments ... > diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c > index 9a15d39..796e68b 100644 > --- a/arch/powerpc/platforms/pseries/hotplug-memory.c > +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c > @@ -101,13 +101,12 @@ static struct property *dlpar_clone_property(struct property *prop, > return new_prop; > } > > -static u32 find_aa_index(struct device_node *dr_node, > - struct property *ala_prop, const u32 *lmb_assoc) > +static int find_aa_index(struct device_node *dr_node, struct property *ala_prop, > + const u32 *lmb_assoc, u32 *aa_index) > { > u32 *assoc_arrays; > - u32 aa_index; > int aa_arrays, aa_array_entries, aa_array_sz; > - int i, index; > + int i, index, rc = -1; It's preferable to leave rc uninitialised until we actually need to initialise it, that gives the compiler the chance to warn us if we use it inadvertently before that. > > /* > * The ibm,associativity-lookup-arrays property is defined to be > @@ -121,18 +120,18 @@ static u32 find_aa_index(struct device_node *dr_node, > aa_array_entries = be32_to_cpu(assoc_arrays[1]); > aa_array_sz = aa_array_entries * sizeof(u32); > > - aa_index = -1; So that would be here: rc = -1; But .. > for (i = 0; i < aa_arrays; i++) { > index = (i * aa_array_entries) + 2; > > if (memcmp(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz)) > continue; > > - aa_index = i; > + *aa_index = i; > + rc = 0; > break; > } The 'rc' variable is basically a boolean now, it means "we found something". And all we do with it in the found case (rc = 0) is test it below and return. So can't we just return directly in the for loop above, rather than breaking? In which case we don't need the rc variable at all. And the whole function may as well return bool, rather than int. Does that make sense? cheers > - if (aa_index == -1) { > + if (rc == -1) { > struct property *new_prop; > u32 new_prop_size; > > @@ -157,10 +156,11 @@ static u32 find_aa_index(struct device_node *dr_node, > * number of entries - 1 since we added its associativity > * to the end of the lookup array. > */ > - aa_index = be32_to_cpu(assoc_arrays[0]) - 1; > + *aa_index = be32_to_cpu(assoc_arrays[0]) - 1; > + rc = 0; > } > > - return aa_index; > + return rc; > } > > static int update_lmb_associativity_index(struct drmem_lmb *lmb)
On 2018/10/9 15:00, Michael Ellerman wrote: > YueHaibing <yuehaibing@huawei.com> writes: >> 'aa_index' is defined as an unsigned value, but find_aa_index >> may return -1 when dlpar_clone_property fails. So we use an rc >> value to track the validation of finding the aa_index instead >> of the 'aa_index' value itself >> >> Fixes: c05a5a40969e ("powerpc/pseries: Dynamic add entires to associativity lookup array") >> Signed-off-by: YueHaibing <yuehaibing@huawei.com> >> --- >> v2: use 'rc' track the validation of aa_index > > Thanks for sending a v2, some more comments ... > >> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c >> index 9a15d39..796e68b 100644 >> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c >> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c >> @@ -101,13 +101,12 @@ static struct property *dlpar_clone_property(struct property *prop, >> return new_prop; >> } >> >> -static u32 find_aa_index(struct device_node *dr_node, >> - struct property *ala_prop, const u32 *lmb_assoc) >> +static int find_aa_index(struct device_node *dr_node, struct property *ala_prop, >> + const u32 *lmb_assoc, u32 *aa_index) >> { >> u32 *assoc_arrays; >> - u32 aa_index; >> int aa_arrays, aa_array_entries, aa_array_sz; >> - int i, index; >> + int i, index, rc = -1; > > It's preferable to leave rc uninitialised until we actually need to > initialise it, that gives the compiler the chance to warn us if we use > it inadvertently before that. > >> >> /* >> * The ibm,associativity-lookup-arrays property is defined to be >> @@ -121,18 +120,18 @@ static u32 find_aa_index(struct device_node *dr_node, >> aa_array_entries = be32_to_cpu(assoc_arrays[1]); >> aa_array_sz = aa_array_entries * sizeof(u32); >> >> - aa_index = -1; > > So that would be here: > rc = -1; > > But .. > >> for (i = 0; i < aa_arrays; i++) { >> index = (i * aa_array_entries) + 2; >> >> if (memcmp(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz)) >> continue; >> >> - aa_index = i; >> + *aa_index = i; >> + rc = 0; >> break; >> } > > The 'rc' variable is basically a boolean now, it means "we found something". > > And all we do with it in the found case (rc = 0) is test it below and return. > > So can't we just return directly in the for loop above, rather than breaking? > > In which case we don't need the rc variable at all. > > And the whole function may as well return bool, rather than int. > > Does that make sense? Yes, will do that in v3. > > cheers > >> - if (aa_index == -1) { >> + if (rc == -1) { >> struct property *new_prop; >> u32 new_prop_size; >> >> @@ -157,10 +156,11 @@ static u32 find_aa_index(struct device_node *dr_node, >> * number of entries - 1 since we added its associativity >> * to the end of the lookup array. >> */ >> - aa_index = be32_to_cpu(assoc_arrays[0]) - 1; >> + *aa_index = be32_to_cpu(assoc_arrays[0]) - 1; >> + rc = 0; >> } >> >> - return aa_index; >> + return rc; >> } >> >> static int update_lmb_associativity_index(struct drmem_lmb *lmb) > > . >
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c index 9a15d39..796e68b 100644 --- a/arch/powerpc/platforms/pseries/hotplug-memory.c +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c @@ -101,13 +101,12 @@ static struct property *dlpar_clone_property(struct property *prop, return new_prop; } -static u32 find_aa_index(struct device_node *dr_node, - struct property *ala_prop, const u32 *lmb_assoc) +static int find_aa_index(struct device_node *dr_node, struct property *ala_prop, + const u32 *lmb_assoc, u32 *aa_index) { u32 *assoc_arrays; - u32 aa_index; int aa_arrays, aa_array_entries, aa_array_sz; - int i, index; + int i, index, rc = -1; /* * The ibm,associativity-lookup-arrays property is defined to be @@ -121,18 +120,18 @@ static u32 find_aa_index(struct device_node *dr_node, aa_array_entries = be32_to_cpu(assoc_arrays[1]); aa_array_sz = aa_array_entries * sizeof(u32); - aa_index = -1; for (i = 0; i < aa_arrays; i++) { index = (i * aa_array_entries) + 2; if (memcmp(&assoc_arrays[index], &lmb_assoc[1], aa_array_sz)) continue; - aa_index = i; + *aa_index = i; + rc = 0; break; } - if (aa_index == -1) { + if (rc == -1) { struct property *new_prop; u32 new_prop_size; @@ -157,10 +156,11 @@ static u32 find_aa_index(struct device_node *dr_node, * number of entries - 1 since we added its associativity * to the end of the lookup array. */ - aa_index = be32_to_cpu(assoc_arrays[0]) - 1; + *aa_index = be32_to_cpu(assoc_arrays[0]) - 1; + rc = 0; } - return aa_index; + return rc; } static int update_lmb_associativity_index(struct drmem_lmb *lmb) @@ -169,6 +169,7 @@ static int update_lmb_associativity_index(struct drmem_lmb *lmb) struct property *ala_prop; const u32 *lmb_assoc; u32 aa_index; + int rc; parent = of_find_node_by_path("/"); if (!parent) @@ -200,11 +201,11 @@ static int update_lmb_associativity_index(struct drmem_lmb *lmb) return -ENODEV; } - aa_index = find_aa_index(dr_node, ala_prop, lmb_assoc); + rc = find_aa_index(dr_node, ala_prop, lmb_assoc, &aa_index); dlpar_free_cc_nodes(lmb_node); - if (aa_index < 0) { + if (rc < 0) { pr_err("Could not find LMB associativity\n"); return -1; }
'aa_index' is defined as an unsigned value, but find_aa_index may return -1 when dlpar_clone_property fails. So we use an rc value to track the validation of finding the aa_index instead of the 'aa_index' value itself Fixes: c05a5a40969e ("powerpc/pseries: Dynamic add entires to associativity lookup array") Signed-off-by: YueHaibing <yuehaibing@huawei.com> --- v2: use 'rc' track the validation of aa_index --- arch/powerpc/platforms/pseries/hotplug-memory.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)