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author | Nathan Fontenot <nfont@austin.ibm.com> | 2010-08-18 09:58:46 +0000 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-09-02 10:07:38 +1000 |
commit | 93f68f1ef787d97ab688f78a01f446e85bb9a496 (patch) | |
tree | 48686ab3564991aba66e47f1a6048ff8a4cbe4c2 /arch/powerpc/platforms/pseries/dlpar.c | |
parent | a28dec2f26013aad89446b1f708f948617bc28a2 (diff) | |
download | blackbird-op-linux-93f68f1ef787d97ab688f78a01f446e85bb9a496.tar.gz blackbird-op-linux-93f68f1ef787d97ab688f78a01f446e85bb9a496.zip |
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) struct property *property; struct property *last_property = NULL; struct cc_workarea *ccwa; + char *data_buf; int cc_token; - int rc; + int rc = -1; cc_token = rtas_token("ibm,configure-connector"); if (cc_token == RTAS_UNKNOWN_SERVICE) return NULL; - spin_lock(&rtas_data_buf_lock); - ccwa = (struct cc_workarea *)&rtas_data_buf[0]; + data_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL); + if (!data_buf) + return NULL; + + ccwa = (struct cc_workarea *)&data_buf[0]; ccwa->drc_index = drc_index; ccwa->zero = 0; - rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL); - while (rc) { + do { + /* Since we release the rtas_data_buf lock between configure + * connector calls we want to re-populate the rtas_data_buffer + * with the contents of the previous call. + */ + spin_lock(&rtas_data_buf_lock); + + memcpy(rtas_data_buf, data_buf, RTAS_DATA_BUF_SIZE); + rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL); + memcpy(data_buf, rtas_data_buf, RTAS_DATA_BUF_SIZE); + + spin_unlock(&rtas_data_buf_lock); + switch (rc) { case NEXT_SIBLING: dn = dlpar_parse_cc_node(ccwa); @@ -197,18 +212,19 @@ struct device_node *dlpar_configure_connector(u32 drc_index) "returned from configure-connector\n", rc); goto cc_error; } + } while (rc); - rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL); +cc_error: + kfree(data_buf); + + if (rc) { + if (first_dn) + dlpar_free_cc_nodes(first_dn); + + return NULL; } - spin_unlock(&rtas_data_buf_lock); return first_dn; - -cc_error: - if (first_dn) - dlpar_free_cc_nodes(first_dn); - spin_unlock(&rtas_data_buf_lock); - return NULL; } static struct device_node *derive_parent(const char *path) |