diff options
author | Nathan Fontenot <nfont@austin.ibm.com> | 2010-08-18 05:58:46 -0400 |
---|---|---|
committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-09-01 20:07:38 -0400 |
commit | 93f68f1ef787d97ab688f78a01f446e85bb9a496 (patch) | |
tree | 48686ab3564991aba66e47f1a6048ff8a4cbe4c2 /arch/powerpc/platforms/pseries/dlpar.c | |
parent | a28dec2f26013aad89446b1f708f948617bc28a2 (diff) |
powerpc/pseries: Correct rtas_data_buf locking in dlpar code
The dlpar code can cause a deadlock to occur when making the RTAS
configure-connector call. This occurs because we make kmalloc calls,
which can block, while parsing the rtas_data_buf and holding the
rtas_data_buf_lock. This an cause issues if someone else attempts
to grab the rtas_data_bug_lock.
This patch alleviates this issue by copying the contents of the rtas_data_buf
to a local buffer before parsing. This allows us to only hold the
rtas_data_buf_lock around the RTAS configure-connector calls.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/platforms/pseries/dlpar.c')
-rw-r--r-- | arch/powerpc/platforms/pseries/dlpar.c | 42 |
1 files changed, 29 insertions, 13 deletions
diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c index 227c1c3d585e..72d8054fa739 100644 --- a/arch/powerpc/platforms/pseries/dlpar.c +++ b/arch/powerpc/platforms/pseries/dlpar.c | |||
@@ -129,20 +129,35 @@ struct device_node *dlpar_configure_connector(u32 drc_index) | |||
129 | struct property *property; | 129 | struct property *property; |
130 | struct property *last_property = NULL; | 130 | struct property *last_property = NULL; |
131 | struct cc_workarea *ccwa; | 131 | struct cc_workarea *ccwa; |
132 | char *data_buf; | ||
132 | int cc_token; | 133 | int cc_token; |
133 | int rc; | 134 | int rc = -1; |
134 | 135 | ||
135 | cc_token = rtas_token("ibm,configure-connector"); | 136 | cc_token = rtas_token("ibm,configure-connector"); |
136 | if (cc_token == RTAS_UNKNOWN_SERVICE) | 137 | if (cc_token == RTAS_UNKNOWN_SERVICE) |
137 | return NULL; | 138 | return NULL; |
138 | 139 | ||
139 | spin_lock(&rtas_data_buf_lock); | 140 | data_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL); |
140 | ccwa = (struct cc_workarea *)&rtas_data_buf[0]; | 141 | if (!data_buf) |
142 | return NULL; | ||
143 | |||
144 | ccwa = (struct cc_workarea *)&data_buf[0]; | ||
141 | ccwa->drc_index = drc_index; | 145 | ccwa->drc_index = drc_index; |
142 | ccwa->zero = 0; | 146 | ccwa->zero = 0; |
143 | 147 | ||
144 | rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL); | 148 | do { |
145 | while (rc) { | 149 | /* Since we release the rtas_data_buf lock between configure |
150 | * connector calls we want to re-populate the rtas_data_buffer | ||
151 | * with the contents of the previous call. | ||
152 | */ | ||
153 | spin_lock(&rtas_data_buf_lock); | ||
154 | |||
155 | memcpy(rtas_data_buf, data_buf, RTAS_DATA_BUF_SIZE); | ||
156 | rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL); | ||
157 | memcpy(data_buf, rtas_data_buf, RTAS_DATA_BUF_SIZE); | ||
158 | |||
159 | spin_unlock(&rtas_data_buf_lock); | ||
160 | |||
146 | switch (rc) { | 161 | switch (rc) { |
147 | case NEXT_SIBLING: | 162 | case NEXT_SIBLING: |
148 | dn = dlpar_parse_cc_node(ccwa); | 163 | dn = dlpar_parse_cc_node(ccwa); |
@@ -197,18 +212,19 @@ struct device_node *dlpar_configure_connector(u32 drc_index) | |||
197 | "returned from configure-connector\n", rc); | 212 | "returned from configure-connector\n", rc); |
198 | goto cc_error; | 213 | goto cc_error; |
199 | } | 214 | } |
215 | } while (rc); | ||
200 | 216 | ||
201 | rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL); | 217 | cc_error: |
218 | kfree(data_buf); | ||
219 | |||
220 | if (rc) { | ||
221 | if (first_dn) | ||
222 | dlpar_free_cc_nodes(first_dn); | ||
223 | |||
224 | return NULL; | ||
202 | } | 225 | } |
203 | 226 | ||
204 | spin_unlock(&rtas_data_buf_lock); | ||
205 | return first_dn; | 227 | return first_dn; |
206 | |||
207 | cc_error: | ||
208 | if (first_dn) | ||
209 | dlpar_free_cc_nodes(first_dn); | ||
210 | spin_unlock(&rtas_data_buf_lock); | ||
211 | return NULL; | ||
212 | } | 228 | } |
213 | 229 | ||
214 | static struct device_node *derive_parent(const char *path) | 230 | static struct device_node *derive_parent(const char *path) |