From 93f68f1ef787d97ab688f78a01f446e85bb9a496 Mon Sep 17 00:00:00 2001 From: Nathan Fontenot Date: Wed, 18 Aug 2010 09:58:46 +0000 Subject: 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 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/dlpar.c | 42 +++++++++++++++++++++++----------- 1 file changed, 29 insertions(+), 13 deletions(-) (limited to 'arch/powerpc/platforms/pseries/dlpar.c') 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) -- cgit v1.2.1