by tip-bot2 for Alexey Makhalov

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Subject: [tip: x86/cache] x86/resctrl: Unwind properly from rdt_enable_ctx()

The following commit has been merged into the x86/cache branch of tip:

Commit-ID: df5f3a1dd8a6d3ddb1f07a10817f735194717422
Gitweb: https://git.kernel.org/tip/df5f3a1dd8a6d3ddb1f07a10817f735194717422
Author: Babu Moger <[email protected]>
AuthorDate: Mon, 16 Oct 2023 19:23:03 -05:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 17 Oct 2023 12:49:02 +02:00

x86/resctrl: Unwind properly from rdt_enable_ctx()

rdt_enable_ctx() enables the features provided during resctrl mount.

Additions to rdt_enable_ctx() are required to also modify error paths
of rdt_enable_ctx() callers to ensure correct unwinding if errors
are encountered after calling rdt_enable_ctx(). This is error prone.

Introduce rdt_disable_ctx() to refactor the error unwinding of
rdt_enable_ctx() to simplify future additions. This also simplifies
cleanup in rdt_kill_sb().

Suggested-by: Reinette Chatre <[email protected]>
Signed-off-by: Babu Moger <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Reviewed-by: Peter Newman <[email protected]>
Reviewed-by: Tan Shaopeng <[email protected]>
Reviewed-by: Fenghua Yu <[email protected]>
Reviewed-by: Reinette Chatre <[email protected]>
Reviewed-by: Ilpo Järvinen <[email protected]>
Tested-by: Peter Newman <[email protected]>
Tested-by: Tan Shaopeng <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 53 +++++++++++++++----------
1 file changed, 32 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 125d12d..d1b5fd7 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2308,14 +2308,6 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable)
return 0;
}

-static void cdp_disable_all(void)
-{
- if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
- resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
- if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
- resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
-}
-
/*
* We don't allow rdtgroup directories to be created anywhere
* except the root directory. Thus when looking for the rdtgroup
@@ -2395,19 +2387,42 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
struct rdtgroup *prgrp,
struct kernfs_node **mon_data_kn);

+static void rdt_disable_ctx(void)
+{
+ resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
+ resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
+ set_mba_sc(false);
+}
+
static int rdt_enable_ctx(struct rdt_fs_context *ctx)
{
int ret = 0;

- if (ctx->enable_cdpl2)
+ if (ctx->enable_cdpl2) {
ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, true);
+ if (ret)
+ goto out_done;
+ }

- if (!ret && ctx->enable_cdpl3)
+ if (ctx->enable_cdpl3) {
ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, true);
+ if (ret)
+ goto out_cdpl2;
+ }

- if (!ret && ctx->enable_mba_mbps)
+ if (ctx->enable_mba_mbps) {
ret = set_mba_sc(true);
+ if (ret)
+ goto out_cdpl3;
+ }
+
+ return 0;

+out_cdpl3:
+ resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
+out_cdpl2:
+ resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
+out_done:
return ret;
}

@@ -2515,13 +2530,13 @@ static int rdt_get_tree(struct fs_context *fc)
}

ret = rdt_enable_ctx(ctx);
- if (ret < 0)
- goto out_cdp;
+ if (ret)
+ goto out;

ret = schemata_list_create();
if (ret) {
schemata_list_destroy();
- goto out_mba;
+ goto out_ctx;
}

closid_init();
@@ -2580,11 +2595,8 @@ out_info:
kernfs_remove(kn_info);
out_schemata_free:
schemata_list_destroy();
-out_mba:
- if (ctx->enable_mba_mbps)
- set_mba_sc(false);
-out_cdp:
- cdp_disable_all();
+out_ctx:
+ rdt_disable_ctx();
out:
rdt_last_cmd_clear();
mutex_unlock(&rdtgroup_mutex);
@@ -2816,12 +2828,11 @@ static void rdt_kill_sb(struct super_block *sb)
cpus_read_lock();
mutex_lock(&rdtgroup_mutex);

- set_mba_sc(false);
+ rdt_disable_ctx();

/*Put everything back to default values. */
for_each_alloc_capable_rdt_resource(r)
reset_all_ctrls(r);
- cdp_disable_all();
rmdir_all_sub();
rdt_pseudo_lock_release();
rdtgroup_default.mode = RDT_MODE_SHAREABLE;